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Severe Maternal Morbidity in Canada: Temporal Trends and Regional Variations, 2003-2016

Open AccessPublished:May 03, 2019DOI:https://doi.org/10.1016/j.jogc.2019.02.014

      Abstract

      Objective

      This study sought to quantify temporal trends and provincial and territorial variations in severe maternal morbidity (SMM) in Canada.

      Methods

      The study used data on all hospital deliveries in Canada (excluding Québec) from 2003 to 2016 to examine temporal trends and from 2012 to 2016 to study regional variations. SMM was identified using diagnosis and intervention codes. Contrasts among periods and regions were quantified using rate ratios (RRs) and 95% confidence intervals (CIs). Temporal changes were also assessed using chi-square tests for trend (Canadian Task Force Classification II-1).

      Results

      The study population included 3 882 790 deliveries between 2003 and 2016 and 1 418 545 deliveries between 2012 and 2016. Severe hemorrhage rates increased from 44.8 in 2003 to 62.4 per 10 000 deliveries in 2012 (P for trend <0.0001) and then declined to 41.8 per 10 000 deliveries in 2016 (P for trend <0.0001). Maternal intensive care unit admission and sepsis rates decreased between 2003 and 2016, whereas rates of stroke, severe uterine rupture, hysterectomy, obstetric embolism, shock, and assisted ventilation increased. Rates of composite SMM in 2012-2016 were higher in Newfoundland and Labrador (RR 1.15; 95% CI 1.04–1.26), Nova Scotia (RR 1.11; 95% CI 1.03–1.19), New Brunswick (RR1.22; 95% CI 1.13–1.32), Manitoba (RR 1.09; 95% CI 1.03–1.15), Saskatchewan (RR 1.15; 95% CI 1.09–1.22), the Yukon (RR 1.74; 95% CI 1.35–2.25), and Nunavut (RR 1.76; 95% CI 1.46–2.11) compared with the rest of Canada, whereas rates were lower in Alberta and British Columbia.

      Conclusion

      This surveillance report helps inform clinical practice and public health policy for improving maternal health in Canada.

      Résumé

      Objectif

      Cette étude visait à quantifier les tendances temporelles et les différences entre les provinces et territoires en matière de morbidité maternelle grave (MMG) au Canada.

      Méthodologie

      L'étude s'est servie de données sur tous les accouchements ayant eu lieu à l'hôpital au Canada (à l'exception du Québec) : de 2003 à 2016 pour les tendances temporelles, et de 2012 à 2016 pour les différences régionales. Les cas de MMG ont été trouvés au moyen de leurs codes de diagnostic et d'intervention. Les différences entre les périodes et les régions ont été quantifiées à l'aide de ratios des taux (RT) et des intervalles de confiance (IC) à 95 %. Les changements temporels ont aussi été évalués avec le test de tendance du chi carré (classification II-1 du Groupe d'étude canadien).

      Résultats

      La population à l'étude totalisait 3 882 790 accouchements pour les années 2003 à 2016 et 1 418 545 accouchements pour les années 2012 à 2016. Le taux d'hémorragie grave par 10 000 accouchements est passé de 44,8 en 2003 à 62,4 en 2012 (P de tendance < 0,0001) puis est descendu à 41,8 en 2016 (P de tendance < 0,0001). Les taux d'admission de la mère aux soins intensifs et de septicémie ont diminué entre 2003 et 2016, alors que les taux d'accident vasculaire cérébral, de rupture utérine grave, d'hystérectomie, d'embolie obstétricale, de choc et de ventilation assistée ont augmenté. Les taux de MMG composite pour la période de 2012 à 2016 étaient plus élevés à Terre-Neuve-et-Labrador (RT : 1,15; IC à 95 % : 1,04-1,26), en Nouvelle-Écosse (RT : 1,11; IC à 95 % : 1,03-1,19), au Nouveau-Brunswick (RT : 1,22; IC à 95 % : 1,13-1,32), au Manitoba (RT : 1,09; IC à 95 % : 1,03-1,15), en Saskatchewan (RT : 1,15; IC à 95 % : 1,09-1,22), au Yukon (RT : 1,74; IC à 95 % : 1,35-2,25) et au Nunavut (RT : 1,76; IC à 95 % : 1,46-2,11) que dans le reste du Canada, et plus bas en Alberta et en Colombie-Britannique.

      Conclusion

      Ce rapport de surveillance permet de guider la pratique clinique et les politiques de santé publique dans l'amélioration de la santé maternelle au Canada.

      Key Words

      INTRODUCTION

      Monitoring and surveillance of severe maternal morbidity (SMM) have received increasing emphasis in recent years, both because of the relative rarity of maternal deaths in high-income countries and because such morbidity has important short- and long-term consequences for maternal health. Temporal changes in maternal characteristics such as age and pre-pregnancy weight have also led to higher rates of pregnancy complications. For instance, the prevalence of pre-existing medical complications, such as chronic hypertension and diabetes mellitus, is substantially higher among women in their 30s and 40s,
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      Pre-pregnancy obesity, another increasingly prevalent maternal characteristic, is associated with higher rates of thromboembolism, pulmonary embolism, cerebrovascular morbidity, sepsis, acute renal failure, eclampsia, and maternal intensive care unit (ICU) admission.
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      Dayan N, Fell DB, Guo Y, et al. Severe maternal morbidity in women with high BMI in IVF and unassisted singleton pregnancies [e-pub ahead of print]. Hum Reprod doi: 10.1093/humrep/dey224, accessed March 27, 2019.

      Population rates of SMM also reflect the quality of medical and obstetric care. Better identification, clinical monitoring, and management of high-risk women result in improved maternal outcomes. Paradoxically, improvements in medical care, especially for women with chronic disease (treatment of infertility is a notable example), have increased the proportion of high-risk pregnancies in recent years.

      Dayan N, Fell DB, Guo Y, et al. Severe maternal morbidity in women with high BMI in IVF and unassisted singleton pregnancies [e-pub ahead of print]. Hum Reprod doi: 10.1093/humrep/dey224, accessed March 27, 2019.

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      Caesarean delivery, which has substantially reduced maternal morbidity and mortality from antepartum hemorrhage, obstructed labour, and other causes over the last several decades, has led to increased rates of adherent placenta in subsequent pregnancies.
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      Surveillance of SMM (i.e., assessment of temporal and regional variation in population rates of serious maternal illnesses) is important for the early identification of adverse changes in maternal health and for quantifying disparities in maternal health among subpopulations. The Canadian Perinatal Surveillance System began a program of extended maternal health surveillance in 2003 by moving beyond maternal mortality surveillance to assess population-based rates of SMM.
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      Temporal trends and regional variations in severe maternal morbidity in Canada, 2003 to 2007.
      This report presents the most recent evaluation of SMM in Canada, according to a newly developed framework for identifying women with serious maternal conditions.

      METHODS

      We included all hospital deliveries in Canada from 2003 to 2016. Information on these deliveries was obtained from the Discharge Abstract Database of the Canadian Institute for Health Information. This database contained records for approximately 98% of all deliveries in Canada (excluding Québec), with information abstracted from medical records by trained personnel using standardized definitions and processes.
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      Uses and limitations of routine hospital admission/separation records for perinatal surveillance.
      Details included maternal and infant characteristics, labour and delivery events, and diagnoses and procedures, with diagnoses coded using the International Statistical Classification of Diseases and Related Health Problems, 10th revision, Canadian version (ICD-10CA), and procedures coded using the Canadian Classification of Health Interventions (CCI). The validity of the information in the Discharge Abstract Database has been assessed against maternal and newborn medical records and shown to reflect the data in medical records accurately.
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      Data quality study of the 2015–2016 Discharge Abstract Database: a focus on hospital harm.

      Defining Severe Maternal Morbidity

      SMM was defined as a set of maternal conditions known to be associated with severe illness and characterized by prolonged hospitalization and high case fatality. Specific SMM subtypes were identified using a comprehensive list of maternal disease diagnoses (e.g., eclampsia), interventions (e.g., assisted ventilation), and conditions that signified organ failure (e.g., acute renal failure). This framework was developed by the Canadian Perinatal Surveillance System after evaluating candidate illnesses on the basis of a priori clinical considerations (related to illness severity), prolonged length of hospital stay, and high case fatality during the delivery admission (Dzakpasu S, Deb-Rinker P, Arbour L, et al. Severe maternal morbidity surveillance: monitoring pregnant women at high risk for prolonged hospitalization and death [submitted for publication]). It represents a formal revision of the previous 2010 definition of SMM
      • Joseph KS
      • Liu S
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      • et al.
      Severe maternal morbidity in Canada, 2003 to 2007: surveillance using routine hospitalization data and ICD-10CA codes.
      and was carried out to address various shortcomings, including the exclusion of severe preeclampsia and HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome cases as a result of coding limitations in the early version of ICD-10CA and the inclusion of conditions that did not necessarily represent SMM per se (e.g., asymptomatic human immunodeficiency virus infection).
      The revised framework included 44 subtypes of SMM (online Appendix Table S1), identified using 76 ICD-10CA diagnosis codes (e.g., O14.1 for severe preeclampsia), 24 CCI intervention codes (e.g., 5.PC.91.HQ for surgical correction of inverted uterus), and three variables specifically collected by the Canadian Institute for Health Information (e.g., red cell transfusion). For ease of analysis and interpretation, we combined the 44 SMM subtypes into 13 broad SMM types: (1) severe preeclampsia, HELLP syndrome, and eclampsia; (2) severe hemorrhage; (3) maternal ICU admission; (4) surgical complications; (5) hysterectomy; (6) sepsis; (7) embolism, shock, and disseminated intravascular coagulation (DIC); (8) assisted ventilation; (9) cardiac conditions; (10) acute renal failure; (11) severe uterine rupture; (12) cerebrovascular accidents; and (13) miscellaneous SMM (online Appendix Table S1).
      Analyses focused on composite SMM, SMM types, and SMM subtypes. SMM types and subtypes were not designed to be mutually exclusive. Thus, a woman requiring assisted ventilation who was admitted to the ICU would have been counted under both the assisted ventilation and ICU admission types of SMM, although she would have been included as a single case of SMM under composite SMM.

      Temporal Trends and Regional Variations in Severe Maternal Morbidity

      Temporal trends in specific SMM types and subtypes were assessed over the 14 years between 2003 and 2016. Because ICD-10CA codes for the identification of severe preeclampsia were not introduced until 2012, rates of this particular SMM (and therefore of composite SMM) were quantified only for the years 2012 to 2016. Temporal trends and regional differences in composite SMM, SMM types, and SMM subtypes were also assessed for the most recent 5-year period (2012-2016).

      Analysis and Ethics Considerations

      The frequency of composite SMM and of SMM types and subtypes was expressed using rates (per 1000 or per 10 000 deliveries) and their 95% confidence intervals (CIs). Rate ratios and 95% CIs were used to contrast rates in different years and between each province or territory and the rest of Canada (excluding Québec). Chi-square tests for linear trend (1 degree of freedom) were used to assess temporal trends in rates. P values were interpreted cautiously on the basis of a priori knowledge and the size of the effect.
      Privacy considerations required the suppression of cells with small values (one to four). All analyses were carried out using SAS software version 9.2 (SAS Institute, Cary, NC). Because the study was based on anonymized data and conducted under the surveillance mandate of the Public Health Agency of Canada, ethics approval was not sought.

      RESULTS

      The study population included 3 882 790 deliveries between 2003 and 2016, of which 1 418 545 occurred between 2012 and 2016.

      Composite Severe Maternal Morbidity

      The rate of composite SMM was 16.1 (95% CI 15.9–16.3) per 1000 deliveries for the period 2012-2016 (22 799 cases (Table 1). The highest SMM rates were observed in the Yukon and Nunavut in 2012-2016 (Table 2). Rates of composite SMM were significantly higher in Newfoundland and Labrador, Nova Scotia, New Brunswick, Manitoba, Saskatchewan, the Yukon, and Nunavut compared with the rest of Canada, whereas rates were significantly lower in Alberta and British Columbia (Table 2).
      Table 1Numbers and rates per 1000 deliveries (and their 95% confidence intervals) of composite severe maternal morbidity in Canada (excluding Québec), 2012-2016
      Composite severe maternal morbidity
      YearNumber of deliveriesNumberRate/100095% CIRate ratio (95% CI)P value for trend
      2012283 788493417.416.9–17.91.00 (reference)
      2013281 565480917.116.6–17.60.98 (0.94–1.02)
      2014284 068431815.214.8–15.70.87 (0.84–0.91)
      2015284 928440515.515.0–15.90.89 (0.85–0.93)
      2016284 196433315.214.8–15.70.88 (0.84–0.91)<0.0001
      Total1 418 54522 79916.115.9–16.3
      Table 2Rates and rate ratios (with 95% confidence intervals) for composite severe maternal morbidity by province and territory, Canada (excluding Quebec), 2012-2016
      Composite severe maternal morbidity
      Province/territoryTotal deliveriesNumberRate per 100095% CIRate ratio
      Rate ratios contrasted the rate of composite severe maternal morbidity in each province or territory versus the rest of Canada (excluding Québec).
      95% CIP valueSevere morbidity categories with significantly higher rates
      Newfoundland and Labrador22 10340018.116.4–19.91.151.04–1.260.007Severe hemorrhage
      Prince Edward Island674511016.313.4–19.61.030.86–1.240.78Hysterectomy
      Nova Scotia41 32072217.516.2–18.81.111.03–1.190.007SPE; severe hemorrhage
      New Brunswick33 46064319.217.8–20.71.221.13–1.32<0.0001SPE; severe hemorrhage; maternal ICU
      Ontario674 68810 88216.115.8–16.41.020.99–1.050.08Severe hemorrhage; severe uterine rupture; cardiac conditions; hysterectomy; maternal ICU
      Manitoba80 514138117.216.3–18.11.091.03–1.150.002Severe hemorrhage; sepsis; surgical complications
      Saskatchewan74 648135118.117.2–19.11.151.09–1.22<0.0001Severe hemorrhage
      Alberta264 658392014.814.4–15.30.920.89–0.95<0.0001Embolism, shock, or DIC; acute renal failure or dialysis; hysterectomy; surgical complications
      British Columbia210 612315215.014.5–15.50.940.90–0.970.0005SPE; sepsis; embolism, shock, or DIC; acute renal failure or dialysis; surgical complications
      Northwest Territories32995717.313.1–22.31.090.84–1.410.55Severe hemorrhage
      Yukon20705727.520.9–35.51.741.35–2.25<0.0001Severe hemorrhage, sepsis, surgical complications
      Nunavut396811027.722.8–33.31.761.46–2.11<0.0001SPE; severe hemorrhage; cardiac conditions; embolism, shock, or DIC; surgical or manual correction of inverted uterus
      Canada1 418 08522 78516.115.9–16.3
      DIC: disseminated intravascular coagulation; ICU: intensive care unit; SPE: severe preeclampsia, eclampsia, or HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome.
      a Rate ratios contrasted the rate of composite severe maternal morbidity in each province or territory versus the rest of Canada (excluding Québec).

      Severe Preeclampsia, HELLP Syndrome, and Eclampsia

      Severe preeclampsia, HELLP syndrome, and eclampsia comprised the most common SMM type. Overall rates did not change between 2012 and 2016 (Figure A, Table 3), although rates of eclampsia alone declined significantly (online Appendix Tables S2S5). Rates of severe preeclampsia, HELLP syndrome, and eclampsia in 2012-2016 were significantly higher in Nova Scotia, New Brunswick, British Columbia, and Nunavut and significantly lower in Ontario and the Northwest Territories compared with the rest of Canada (online Appendix Table S4). The proportion of women with eclampsia expressed as a proportion of women with severe preeclampsia, HELLP syndrome, and eclampsia was 8.4% in Canada in 2012-2016 (online Appendix Table S6).
      Figure
      FigureTemporal trends in different types of severe maternal morbidity, Canada (excluding Québec), 2003-2016. (A) Severe (Sev.) preeclampsia, HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome, eclampsia, ICU (intensive care unit) admission, and sepsis (data on severe preeclampsia, HELLP syndrome, and eclampsia available for years 2012-2016 only. (B) Severe hemorrhage, hysterectomy, and cardiac conditions. (C) Embolism, shock, disseminated intravascular coagulation (DIC) severe uterine rupture, surgical complications. (D) Assisted ventilation, acute renal failure, dialysis, cerebrovascular accident.
      Table 3Numbers and rates (per 10 000 deliveries) of severe maternal morbidity types in Canada (excluding Québec), 2003 and 2012-2016
      Year
      Type of severe morbidity
      See online Appendix Table S1 for the severe maternal morbidity subtypes included under each type of severe maternal morbidity.
      200320122013201420152016Rate ratio 2016 vs. 2012 (95% CI)P for trendRate ratio 2016 vs. 2003 (95% CI)P for trend
      Number of deliveries247 159283 788281 565284 068284 928284 196
      SPE, HELLP, eclampsia: number159016381568157415530.980.20
       Rate56.058.255.255.254.60.91–1.05
      Severe hemorrhage: number1107177216741229122311870.67<0.00010.93<0.0001
      Temporal trend in severe hemorrhage and surgical complications increased significantly from 2003 to 2012 (P value for trend <0.0001) and then decreased significantly from 2012 to 2016 (P value for trend <0.0001).
       Rate44.862.459.543.342.941.80.62–0.720.86–1.01
      Maternal ICU admission: number5965225515195745631.080.190.820.0005
       Rate24.118.419.618.320.119.80.96–1.210.73–0.92
      Surgical complications: number3496205425785354770.77<0.00011.19<0.0001
       Rate14.121.819.220.318.816.80.68–0.871.04–1.36
      Hysterectomy: number3134333934034304501.040.321.25<0.0001
       Rate12.715.314.014.215.115.80.91–1.181.08–1.44
      Sepsis: number4262572602842512440.950.450.50<0.0001
       Rate17.29.19.210.08.88.60.80–1.130.43–0.58
      Embolism, shock, DIC: number1322011851462202211.100.101.460.0001
       Rate5.37.16.65.17.77.80.91–1.331.17–1.81
      Assisted ventilation: number671861811562112061.110.122.67<0.0001
       Rate2.76.66.45.57.47.20.91–1.352.03–3.52
      Cardiac conditions: number1631771781621941760.990.790.940.32
       Rate6.26.26.35.76.86.20.81–1.220.76–1.16
      Acute renal failure: number431021191011581671.63<0.00013.38<0.0001
       Rate1.73.64.23.65.55.91.28–2.092.42–4.72
      Severe uterine rupture: number2735403549451.280.161.450.003
       Rate0.91.21.41.21.71.60.83–2.000.90–2.34
      Cerebrovascular accident: number1325212922391.560.082.610.0004
       Rate0.530.880.751.020.771.370.94–2.571.39–4.89
      DIC: disseminated intravascular coagulation; HELLP: hemolysis, elevated liver enzymes, low platelet count syndrome; ICU: intensive care unit; SPE: severe preeclampsia.
      a See online Appendix Table S1 for the severe maternal morbidity subtypes included under each type of severe maternal morbidity.
      b Temporal trend in severe hemorrhage and surgical complications increased significantly from 2003 to 2012 (P value for trend <0.0001) and then decreased significantly from 2012 to 2016 (P value for trend <0.0001).
      Table 4Numbers and rates (per 10 000 deliveries) of severe maternal morbidity types by province/territory, Canada (excluding Québec), 2012-2016
      Province or territory
      Bold numbers indicate that the rate in the province or territory was significantly different (P value <0.05) from the rate in the rest of Canada (excluding Québec).
      Types of severe maternal morbidity
      See online Appendix Table S1 for the severe maternal morbidity subtypes included under each type of severe maternal morbidity.
      NLPENSNBONMBSKABBCNTYTNU
      Number of deliveries22 103674541 32033 460674 68880 51474 648264 658210 612329920703968
      SPE, HELPP, eclampsia: number1233531226735834303901414131581032
       Rate55.651.975.5↑79.8↑53.1↓53.452.253.462.4↑24.2↓48.380.6↑
      Severe hemorrhage: number165322372313,7324506141071439272261
       Rate74.7↑47.457.4↑69.0↑55.3↑55.9↑82.3↑40.5↓20.8↓81.8↑106.3↑153.7↑
      Maternal ICU admission: number656411291552961503952681165
       Rate29.48.99.9↓38.6↑23.0↑11.9↓20.114.9↓12.7↓33.329.012.6
      Surgical complications: number369736410842871195604887139
       Rate16.313.317.719.116.1↓35.6↑15.9↓21.2↑23.2↑21.262.8↑22.7
      Hysterectomy: number2320303610749095433298<5<5<5
       Rate10.429.7↑7.3↓10.8↓15.9↑11.2↓12.716.4↑14.1
      Sepsis: number17102416544987419730167<5
       Rate7.714.85.8↓4.8↓8.1↓12.2↑9.97.4↓14.3↑18.233.8↑
      Embolism, shock, DIC: number13<5281842052602051660<57
       Rate5.96.85.46.2↓6.58.07.7↑7.9↑0.017.6↑
      Assisted ventilation: number15<5201150650621491160<5<5
       Rate6.84.83.3↓7.56.28.35.6↓5.50.0
      Cardiac conditions: number12<527164505052153110<5<56
       Rate5.46.54.86.7↑6.27.05.85.2↓15.1↑
      Acute renal failure: number11<591625927301441440<50
       Rate5.03.02.2↓4.83.8↓3.44.05.4↑6.8↑0.00.0
      Severe uterine rupture: number<5<55712515161415<500
       Rate1.22.11.9↑1.92.10.5↓0.7↓0.00.0
      Cerebrovascular accident: number<50<5072107261500<5
       Rate0.00.01.11.20.91.00.70.00.0
      DIC: disseminated intravascular coagulation; HELLP: hemolysis, elevated liver enzymes, low platelet count syndrome; ICU: intensive care unit; SPE: severe preeclampsia; : the rate was significantly lower; ↑: the rate was significantly higher (rate ratios in online Appendix Table S4).
      a See online Appendix Table S1 for the severe maternal morbidity subtypes included under each type of severe maternal morbidity.
      b Bold numbers indicate that the rate in the province or territory was significantly different (P value <0.05) from the rate in the rest of Canada (excluding Québec).

      Severe Hemorrhage

      Severe hemorrhage was also relatively common, and rates did not change from 2003 to 2016. However, the temporal pattern was unexpected: Rates increased from 2003 to 2012 before declining (Figure B, Table 3). Temporal trends in severe hemorrhage subtypes showed that severe postpartum hemorrhage was largely responsible for the overall pattern in severe hemorrhage (online Appendix Table S2). In 2012-2016, rates of severe hemorrhage were significantly higher in Newfoundland and Labrador, Nova Scotia, New Brunswick, Ontario, Manitoba, Saskatchewan, Northwest Territories, the Yukon, and Nunavut compared with the rest of Canada, whereas rates were significantly lower in Alberta and British Columbia (online Appendix Table S4).

      Intensive Care Unit Admission

      Maternal ICU admissions declined between 2003 and 2016 (Figure A, Table 3). ICU admission in 2012-2016 was significantly more common in New Brunswick and Ontario compared with the rest of Canada and significantly less frequent in Nova Scotia, Manitoba, Alberta, and British Columbia (online Appendix S2S5).
      Appendix Table S1Severe maternal morbidity (SMM) types, subtypes, and International Classification of Diseases (ICD-10CA) and Canadian Classification of Interventions (CCI) codes for identifying each severe morbidity subtype
      SMM typeSMM subtypeICD-10CA, CCI codes and other variables
      SPE, HELLP, eclampsiaSevere pre-eclampsia, HELLP syndromeO14.1, O14.2
      EclampsiaO15
      Severe hemorrhagePlacenta previa with hemorrhage and red cell transfusionO44.1 + RBCTRNSF=‘Y’
      Placental abruption with coagulation defectO45.0
      Antepartum hemorrhage with coagulation defectO46.0
      Intrapartum hemorrhage with coagulation defectO67.0
      Intrapartum hemorrhage with red cell transfusionO67 + RBCTRNSF=‘Y’
      Postpartum hemorrhage with red cell transfusion, procedures to the uterus or hysterectomyO72 + any of the following:

      • RBCTRNSF=‘Y’, or

      • (1.RM.13, 1.KT.51, 5.PC.91.LA or 5.PC.91.HV) + RBCTRNSF = 1, or

      • (5.MD.60.RC, 5.MD.60.RD, 5.MD.60.KE, 5.MD.60.CB or 1.RM.89.LAb), or

      • 1.RM.87.LA-GX

      bNote: 1.RM.89.LA is included only if codes 1. PL.74, 1.RS.74 or 1.RS.80 are NOT also present
      Curettage with red cell transfusion(5.PC.91.GA, 5.PC.91.GC or 5.PC.91.GD) + RBCTRNSF=‘Y’
      Maternal ICU admissionMaternal ICU admissionFTSPCU in (‘10’,’20’,’25’,’30’,’35’,’40’,’45’,’60’, ‘80’)
      Surgical complicationsComplications of obstetric surgery and proceduresO75.4
      Evacuation of incisional hematoma with RBC transfusion5.PC.73.JS + RBCTRNSF=‘Y’
      Repair of bladder, urethra, or intestine5.PC.80.JR, 1.NK.80 or 1.NM.80
      Reclosure of caesarean wound with RBC transfusion(5.PC.80.JM or 5.PC.80.JH) + RBCTRNSF=‘Y’
      HysterectomyCaesarean hysterectomy5.MD.60.RC, 5.MD.60.RD, 5.MD.60.KE, 5.MD.60.CB
      Hysterectomy using an open approach (without bladder neck suspension, suspension of vaginal vault or pelvic floor repair)1.RM.89.LAc (exclude if 1.PL.74, 1.RS.74 or 1.RS.80 code also present) or 1.RM.87.LA-GX
      Note: 1.RM.89.LA is included only if codes 1.PL.74, 1.RS.74 or 1.RS.80 are NOT also present
      SepsisPuerperal sepsisO85
      Septicemia during labourO75.3
      Embolism, shock, DICObstetric shockO75.1, R57, T80.5 or T88.6
      Obstetric embolismO88
      Disseminated intravascular coagulationD65
      Assisted ventilationAssisted ventilation through endotracheal tube1.GZ.31.CA-ND
      Assisted ventilation through tracheostomy1.GZ.31.CR-ND
      Cardiac conditionsCardiac complications of anesthesiaO74.2, O89.1
      CardiomyopathyO90.3, I42, I43
      Cardiac arrest and resuscitationI46, I49.0, 1.HZ.09, 1.HZ.30
      Myocardial infarctionI21, I22
      Pulmonary edema and heart failureI50, J81
      Acute renal failureAcute renal failureO90.4, N17, N19 or N99.0
      Dialysis1.PZ.21
      Severe uterine ruptureRupture of the uterus with red cell transfusion, procedures to the uterus or hysterectomy(O71.0 or O71.1) + any of the following:

      • RBCTRNSF=‘Y’, or

      • (1.RM.13, 1.KT.51, 5.PC.91.LA or 5.PC.91.HV) + RBCTRNSF=‘Y’, or

      • (5.MD.60.RC, 5.MD.60.RD, 5.MD.60.KE, 5.MD.60.CB or 1.RM.89.LAa), or

      • 1.RM.87.LA-GX

      aNote: 1.RM.89.LA is included only if codes 1. PL.74, 1.RS.74 or 1.RS.80 are NOT also present
      Cerebrovascular accidentsCerebral venous thrombosis in pregnancyO22.5
      Cerebral venous thrombosis in the puerperiumO87.3
      Subarachnoid and intracranial hemorrhage, cerebral infarctionI60, I61, I62, I63 or I64
      Other typesAcute fatty liver with red cell transfusion or plasma transfusionO26.6 + (RBCTRNSF=‘Y’ or PLSTRNSF=’Y’)
      Hepatic failureK71 or K72
      Cerebral edema or comaG93.6 or R40.2
      Pulmonary, cardiac, and CNS complications of anesthesia during pregnancy, labour, delivery or the puerperiumO29.0, O29.1, O29.2, O89.0, O89.1, O89.2, O74.0, O74.1, O74.2 or O74.3
      Status asthmaticusJ45.01, J45.11, J45.81 or J45.91
      Adult respiratory distress syndromeJ80
      Acute abdomenK35, K37, K65, N73.3 or N73.5
      Surgical or manual correction of inverted uterus for vaginal births only5.PC.91.HQ or 5.PC.91.HP, restricted to vaginal births (i.e., absence of caesarean code 5.MD.60)
      Sickle cell anemia with crisisD57.0
      Acute psychosisF53.1 or F23
      Status epilepticusG41
      HIV diseaseB20-24, O98.7
      Notes on selected diagnostic and procedure codes
      • Canadian Institute for Health Information coding specific to severe preeclampsia and HELLP (O14.1 and O14.2) began in 2012. The conditions under acute fatty liver (O26.6) - were expanded in ICD-10-CA version 2009, to add codes for the sixth digits of “2” (Delivered, with mention of postpartum complication) and “4” (Postpartum condition or complication). Previously postpartum liver disorders may have been captured at O90.802 and O90.804 Other complications of the puerperium, not elsewhere classified, respectively. In addition, in ICD-10-CA version 2009 the conditions included in this code were expanded to include “Cholestasis (intrahepatic) in pregnancy” and “Obstetric cholestasis.” Previously, cholestasis in pregnancy would have been classified as O99.6 Diseases of the digestive system complicating pregnancy, childbirth and the puerperium which included conditions in K80-K93, and more specifically, K83.1 Cholestasis NEC.
      • The CCI code 5.PC.91.HV Interventions to uterus (following delivery or abortion), compression using intrauterine balloon was introduced in CCI version 2012. Previously, this intervention may have been captured by code 5.PC.91.HT Interventions to uterus (following delivery or abortion) uterine (and vaginal) packing.
      Appendix Table S2Temporal trends in severe maternal morbidity subtypes, Canada (excluding Quebec), 2003 to 2016 (rates expressed per 10,000 deliveries)
      Severe maternal morbidity subtypes20032004200520062007200820092010201120122013201420152016P for trend
      Severe preeclampsia, and HELLP syndrome---------51.353.651.051.549.90.24
      Eclampsia12.310.79.56.65.76.15.95.55.64.94.94.54.05.3<0.0001
      Placenta previa with hemorrhage with red cell transfusion3.93.74.13.43.94.54.95.34.65.05.32.82.82.90.12
      Placental abruption with coagulation defect2.11.71.91.31.61.72.01.61.41.91.72.42.01.60.52
      Antepartum hemorrhage with coagulation defect0.650.840.420.260.600.600.630.570.390.460.630.450.380.840.90
      Intrapartum hemorrhage with coagulation defect1.20.731.10.730.710.810.770.780.570.910.780.590.800.700.06
      Intrapartum hemorrhage with red cell transfusion2.82.12.62.11.72.21.82.51.93.53.22.11.91.70.62
      Postpartum hemorrhage with red cell transfusion, procedures to the uterus or hysterectomy37.539.141.140.345.551.049.451.654.554.052.136.637.836.20.24
      cells with small numerators (>0 and <5) suppressed.
      Curettage with RBC transfusion7.57.78.16.87.28.48.48.98.27.98.05.86.44.90.0002
      Maternal ICU admission24.120.920.719.818.519.420.318.618.118.419.618.320.119.80.001
      Complications of obstetric surgery and procedures6.75.46.66.76.16.27.58.89.612.610.512.19.98.3<0.0001
      Evacuation of incisional hematoma with red cell transfusion0.690.650.600.660.390.420.420.600.570.560.430.320.350.320.008
      Repair of bladder, urethra, or intestine6.37.26.95.16.87.15.75.87.07.57.07.27.97.20.007
      Reclosure of caesarean wound0.731.01.21.41.01.51.91.71.61.71.51.30.951.20.15
      Caesarean hysterectomy1.71.01.52.22.42.02.83.33.03.13.73.23.54.0<.0001
      Hysterectomy – open approach11.011.012.010.311.711.811.211.812.512.210.311.011.611.90.47
      Septicemia during labour3.01.81.82.01.51.51.61.81.72.12.12.02.32.10.84
      Puerperal sepsis14.313.211.88.88.88.27.47.26.76.97.28.06.56.5<0.0001
      Obstetric shock1.92.82.02.52.42.72.72.82.83.63.12.43.94.2<0.0001
      Obstetric embolism2.73.42.82.92.62.83.13.32.92.93.02.23.33.4<0.0001
      Disseminated intravascular coagulation0.850.610.341.00.781.10.630.820.670.880.850.630.840.770.59
      Assisted ventilation through endotracheal tube2.73.33.64.64.96.35.66.15.96.56.45.47.37.2<0.0001
      Assisted ventilation through tracheostomy
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.3
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.20.2
      cells with small numerators (>0 and <5) suppressed.
      0.04
      Cardiac complications of anesthesia0.570.270.600.440.490.490.560.320.500.350.530.350.460.280.27
      Cardiomyopathy1.61.81.62.01.91.91.91.62.31.92.82.52.72.5<0.0001
      Cardiac arrest and resuscitation0.690.770.720.621.21.00.801.00.461.10.751.01.11.00.09
      Myocardial infraction
      cells with small numerators (>0 and <5) suppressed.
      0.190.23
      cells with small numerators (>0 and <5) suppressed.
      0.00
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.21
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.34
      Pulmonary edema and heart failure4.23.84.44.12.93.93.93.33.03.13.12.53.02.7<0.0001
      Acute renal failure1.61.71.92.82.32.52.23.23.03.43.93.45.35.7<0.0001
      Dialysis0.360.230.420.480.420.320.350.320.350.460.460.630.590.450.05
      Rupture of the uterus with red cell transfusion, procedures to the uterus or hysterectomy1.10.921.21.01.31.11.01.51.51.21.41.21.71.60.003
      Cerebral venous thrombosis in pregnancy
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.190.26
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.170.180.250.21
      cells with small numerators (>0 and <5) suppressed.
      0.280.350.280.003
      Cerebral venous thrombosis in the puerperium
      cells with small numerators (>0 and <5) suppressed.
      0.000.00
      cells with small numerators (>0 and <5) suppressed.
      0.00
      cells with small numerators (>0 and <5) suppressed.
      0.00
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.00
      cells with small numerators (>0 and <5) suppressed.
      0.19
      Subarachnoid and intracranial hemorrhage, cerebral infarction0.400.500.500.600.400.700.600.800.400.630.630.700.421.100.02
      Cerebral edema or coma
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.26
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.280.18
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.38
      Hepatic failure0.530.340.260.220.320.600.24
      cells with small numerators (>0 and <5) suppressed.
      0.28
      cells with small numerators (>0 and <5) suppressed.
      0.180.350.390.180.08
      Acute fatty liver with red cell transfusion or plasma transfusion0.360.190.340.480.490.280.910.781.11.21.10.71.31.0<0.0001
      Pulmonary, cardiac, and CNS complications of anaesthesia during pregnancy, the puerperium or labour and delivery1.61.01.51.21.31.61.61.21.31.30.91.01.21.20.07
      Status asthmaticus0.320.310.23
      cells with small numerators (>0 and <5) suppressed.
      0.280.320.210.21
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.28
      cells with small numerators (>0 and <5) suppressed.
      cells with small numerators (>0 and <5) suppressed.
      0.170.05
      Adult respiratory distress syndrome0.530.650.570.370.670.700.560.390.460.460.390.350.390.390.03
      Acute abdomen0.930.920.570.811.020.880.840.780.881.260.630.700.630.870.62
      Surgical or manual correction of inverted uterus for vaginal births only1.51.41.00.81.10.71.30.821.31.11.40.70.90.70.04
      Sickle cell anemia with crisis0.200.310.300.330.390.180.310.180.500.250.350.310.420.660.03
      Acute psychosis0.400.690.45
      cells with small numerators (>0 and <5) suppressed.
      0.420.490.800.460.420.420.490.170.210.210.02
      Status epilepticus0.240.190.190.180.140.110.240.360.320.180.560.280.240.420.01
      HIV disease1.050.990.720.771.130.911.192.132.332.041.741.971.861.97<0.0001
      low asterisk cells with small numerators (>0 and <5) suppressed.
      Appendix Table S3Number and rate (per 10,000 deliveries) of severe maternal morbidity subtypes, Canada (excluding Quebec), 2012 to 2016
      2012-2016
      Severe maternal morbidity subtypeNumber of casesRate/10,00095% CIP value for trend
      Severe preeclampsia and HELLP syndrome730051.550.3 - 52.70.24
      Eclampsia6684.74.4 - 5.10.91
      Placenta previa with hemorrhage and RBC transfusion5313.73.4 - 4.1<0.0001†
      Placental abruption with coagulation defect2751.91.7 - 2.20.64
      Antepartum hemorrhage with coagulation defect790.60.4 - 0.70.24
      Intrapartum hemorrhage with coagulation defect1070.80.6 - 0.90.40
      Intrapartum hemorrhage with RBC transfusion3522.52.2 - 2.8<0.0001†
      Postpartum hemorrhage with RBC transfusion or procedures to the uterus or hysterectomy614543.342.2 - 44.4<0.0001†
      Curettage with RBC transfusion9346.66.2 - 7.0<0.0001†
      Maternal ICU admission272919.218.5 - 20.00.19
      Complications of obstetric surgery and procedures151610.710.2 -11.2<0.0001†
      Evacuation of incisional hematoma with red cell transfusion560.40.3 - 0.50.13
      Repair of bladder, urethra, or intestine10447.46.9 - 7.80.81
      Reclosure of caesarean wound1871.31.1 - 1.50.02
      Caesarean hysterectomy4963.53.2-3.80.14
      Hysterectomy – open approach1,61711.410.9-12.00.76
      Septicemia during labour3022.11.9 - 2.40.93
      Puerperal sepsis99776.6 - 7.50.38
      Obstetric shock4863.43.1 - 3.70.05*
      Obstetric embolism42232.7 - 3.30.23
      Disseminated intravascular coagulation1130.80.7 - 1.00.67
      Assisted ventilation through endotracheal tube9286.56.1 - 7.00.14
      Assisted ventilation through tracheostomy190.10.1 - 0.20.42
      Cardiac complications of anesthesia560.40.3 - 0.50.56
      Cardiomyopathy3522.52.2 - 2.80.23
      Cardiac arrest and resuscitation14110.8 - 1.20.78
      Myocardial infraction130.090.05 - 0.150.69
      Pulmonary edema and heart failure4102.92.6 - 3.20.31
      Acute renal failure6204.44.0 - 4.7<0.0001*
      Dialysis740.50.4 - 0.70.76
      Rupture of the uterus with red cell transfusion, procedures to the uterus or hysterectomy2041.41.2 - 1.70.16
      Cerebral venous thrombosis in pregnancy350.20.2 - 0.30.19
      Cerebral venous thrombosis in the puerperium60.040.01 - 0.090.39
      Subarachnoid, intracranial hemorrhage, cerebral infarction, stroke980.70.6 - 0.80.21
      Cerebral edema or coma130.10.1 - 0.20.85
      Hepatic failure340.20.2 - 0.30.23
      Acute fatty liver with red cell or plasma transfusion1481.00.9 - 1.20.75
      Pulmonary, cardiac, and CNS complications of anaesthesia1591.11.0 - 1.30.98
      Status asthmaticus240.20.1 - 0.30.66
      Adult respiratory distress syndrome560.40.3 - 0.50.69
      Acute abdomen1170.80.7 - 1.00.14
      Surgical or manual correction of inverted uterus for vaginal births only1351.00.8 - 1.10.04†
      Sickle cell anemia with crisis560.40.3 - 0.50.01*
      Acute psychosis430.30.2 - 0.40.03†
      Status epilepticus480.30.3 - 0.40.62
      HIV disease2721.91.7 - 2.20.97
      *Test for temporal trend indicates significant increase and †indicates significant decrease in rates between 2012 and 2016.
      Appendix Table S4Rate ratios and 95% confidence intervals expressing the relative rate of severe maternal morbidity types in each province/territory compared with the rest of Canada (excluding Quebec), Canada, 2012-2016
      Severe maternal morbidity category/ Province or territoryNLPENSNBONMB
      Severe pre-eclampsia, eclampsia, HELLP
      Rate ratio1.000.931.371.440.910.95
      95% CI0.83-1.190.67-1.291.22-1.531.28-1.630.87-0.950.87-1.05
      P value0.990.72<0.0001<0.0001<0.00010.35
      Severe hemorrhage
      Rate ratio1.510.951.151.401.231.13
      95% CI1.29-1.760.67-1.341.01-1.311.22-1.591.17-1.291.03-1.24
      P value<0.00010.840.03<0.0001<0.00010.01
      Maternal ICU admission
      Rate ratio1.540.460.512.061.460.61
      95% CI1.21-1.970.21-1.030.37-0.691.72-2.451.35-1.570.50-0.74
      P value0.00060.07<0.0001<0.0001<0.0001<0.0001
      Surgical complications
      Rate ratio0.840.690.910.990.721.94
      95% CI0.60-1.160.36-1.320.72-1.150.77-1.260.66-0.771.71-2.19
      P value0.330.320.450.96<0.0001<0.0001
      Hysterectomy
      Rate ratio0.702.000.480.721.140.74
      95% CI0.46-1.051.29-3.110.34-0.690.52-1.001.05-1.250.60-0.92
      P value0.100.003<0.00010.050.0020.006
      Sepsis
      Rate ratio0.841.630.630.520.801.36
      95% CI0.52-1.350.87-3.030.42-0.940.32-0.850.71-0.891.11-1.67
      P value0.540.180.020.006<0.00010.004
      Embolism, shock, DIC
      Rate ratio0.860.220.990.780.840.94
      95% CI0.50-1.480.03-1.530.68-1.440.49-1.240.74-0.950.71-1.24
      P value0.670.150.970.350.0070.71
      Assisted ventilation
      Rate ratio1.030.670.730.491.290.93
      95% CI0.62-1.710.22-2.080.47-1.130.27-0.891.13-1.460.70-1.24
      P value0.920.650.180.020.00010.69
      Cardiac conditions
      Rate ratio0.870.951.050.761.151.00
      95% CI0.49-1.540.36-2.540.72-1.540.47-1.251.00-1.310.75-1.33
      P value0.730.880.760.320.050.96
      Acute renal failure
      Rate ratio1.100.650.471.050.740.73
      95% CI0.60-1.990.16-2.610.24-0.910.64-1.730.63-0.870.49-1.07
      P value0.880.750.030.940.00020.12
      Severe uterine rupture
      Rate ratio1.262.070.841.471.741.32
      95% CI0.47-3.400.51-8.340.34-2.030.69-3.121.32-2.310.78-2.23
      P value0.560.250.850.350.00010.29
      Cerebrovascular accidents
      Rate ratio0.950.000.500.001.261.33
      95% CI0.24-3.84-0.12-2.02-0.90-1.770.70-2.53
      P value0.780.860.460.080.200.35
      Severe maternal morbidity category/ Province or territorySKABBCNTYUNU
      Severe pre-eclampsia, eclampsia, HELLP
      Rate ratio0.930.951.140.430.861.45
      95% CI0.84-1.030.89-1.001.08-1.210.22-0.870.47-1.611.02-2.04
      P value0.180.07<0.00010.020.750.04
      Severe hemorrhage
      Rate ratio1.710.780.381.642.133.10
      95% CI1.57-1.860.73-0.830.34-0.421.13-2.391.41-3.232.41-3.98
      P value<0.0001<0.0001<0.00010.020.0005<0.0001
      Maternal ICU admission
      Rate ratio1.050.740.631.741.510.66
      95% CI0.89-1.240.66-0.820.55-0.710.96-3.140.68-3.360.27-1.57
      P value0.60<0.0001<0.00010.100.440.44
      Surgical complications
      Rate ratio0.811.111.241.093.251.17
      95% CI0.68-0.981.02-1.221.12-1.360.52-2.301.89-5.600.61-2.25
      P value0.030.02<0.00010.97<0.00010.77
      Hysterectomy
      Rate ratio0.851.130.940.610.650.68
      95% CI0.69-1.041.01-1.250.84-1.070.20-1.900.16-2.600.25-1.81
      P value0.130.030.360.390.540.56
      Sepsis
      Rate ratio1.090.781.731.993.710.55
      95% CI0.86-1.380.67-0.911.52-1.970.89-4.451.77-7.800.14-2.20
      P value0.510.002<0.00010.130.00080.60
      Embolism, shock, DIC
      Rate ratio1.181.161.180.001.412.59
      95% CI0.91-1.541.00-1.361.00-1.40-0.35-5.641.23-5.43
      P value0.230.050.050.180.660.02
      Assisted ventilation
      Rate ratio1.270.820.810.002.191.52
      95% CI0.98-1.650.69-0.980.67-0.98-0.71-6.800.57-4.07
      P value0.080.030.030.290.160.34
      Cardiac conditions
      Rate ratio1.130.910.820.970.782.44
      95% CI0.85-1.490.77-1.090.67-1.000.24-3.900.11-5.511.09-5.44
      P value0.450.330.050.760.850.04
      Acute renal failure
      Rate ratio0.881.261.650.002.130.00
      95% CI0.61-1.271.04-1.511.37-1.99-0.53-8.53-
      P value0.550.02<0.00010.410.240.43
      Severe uterine rupture
      Rate ratio1.530.320.462.110.000.00
      95% CI0.92-2.550.19-0.550.27-0.770.30-15.1--
      P value0.11<0.00010.0020.380.710.93
      Cerebrovascular accidents
      Rate ratio0.981.040.720.000.002.66
      95% CI0.46-2.110.68-1.590.42-1.23--0.37-19.0
      P value0.880.950.280.740.490.84
      Statistically significant differences indicated by bold text.
      Appendix Table S5Numbers, rates (per 10,000 deliveries) and 95% confidence intervals for severe maternal morbidity subtypes, Canada (excluding Quebec), 2012 to 2016
      Severe maternal morbidity subtype/Province or territoryNLPENSNBONMB
      Number of deliveries22,1036,74541,32033,460674,68880,514
      Severe preeclampsia and HELLP syndrome49.8

      40.9 - 60.0
      48.9

      33.7 - 68.6
      73.3

      65.3 - 82.0
      77.4

      68.3 - 87.4
      47.6

      46.0 - 49.3
      46.9

      42.3 - 51.9
      Eclampsia7.2

      4.1 - 11.8
      Information suppressed because of small cell size (>0 and <5).
      2.2

      1.0 - 4.1
      2.7

      1.2 - 5.1
      5.8

      5.2 - 6.4
      7.0

      5.3 - 9.0
      Placenta previa with hemorrhage with RBC transfusion4.5

      2.2 - 8.3
      Information suppressed because of small cell size (>0 and <5).
      3.4

      1.8 - 5.7
      3.9

      2.1 - 6.6
      5.0

      4.5 - 5.6
      3.2

      2.1 - 4.7
      Placental abruption with coagulation defect
      Information suppressed because of small cell size (>0 and <5).
      0.01.9

      0.8 - 3.8
      Information suppressed because of small cell size (>0 and <5).
      2.5

      2.1 - 2.9
      2.0

      1.1 - 3.2
      Antepartum hemorrhage with coagulation defect
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.4

      0.3 - 0.6
      Information suppressed because of small cell size (>0 and <5).
      Intrapartum hemorrhage with coagulation defect
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      1.5

      0.5 - 3.5
      0.6

      0.4 - 0.8
      Information suppressed because of small cell size (>0 and <5).
      Intrapartum hemorrhage with red cell transfusion4.5

      2.2 - 8.3
      Information suppressed because of small cell size (>0 and <5).
      5.8

      3.7 - 8.6
      4.2

      2.3 - 7.0
      2.7

      2.3 - 3.1
      2.6

      1.6 - 4.0
      Postpartum hemorrhage with red cell transfusion, procedures to the uterus or hysterectomy65.1

      55.0 - 76.7
      41.5

      27.6 - 59.9
      51.3

      44.6 - 58.7
      61.0

      52.9 - 69.9
      47.5

      45.9 - 49.2
      49.4

      44.7 - 54.5
      Curettage with RBC transfusion10.0

      6.2 - 15.1
      8.9

      3.3 - 19.4
      3.1

      1.7 - 5.4
      10.5

      7.3 - 14.5
      8.2

      7.6 - 9.0
      8.6

      6.7 - 10.8
      Maternal ICU admission29.4

      22.7 - 37.5
      8.9

      3.3 - 19.4
      9.9

      7.1 - 13.5
      38.6

      32.2 - 45.8
      23.0

      21.9 - 24.2
      11.9

      9.7 - 14.6
      Complications of obstetric surgery and procedures3.6

      1.6 - 7.1
      Information suppressed because of small cell size (>0 and <5).
      6.8

      4.5 - 9.8
      6.9

      4.4 - 10.3
      9.1

      8.4 - 9.8
      22.9

      19.7 - 26.4
      Evacuation of incisional hematoma with RBC transfusion
      Information suppressed because of small cell size (>0 and <5).
      0.01.7

      0.7 - 3.5
      Information suppressed because of small cell size (>0 and <5).
      0.4

      0.3 - 0.6
      Information suppressed because of small cell size (>0 and <5).
      Repair of bladder, urethra, or intestine10.0

      6.2 - 15.1
      8.9

      3.3 - 19.4
      7.0

      4.7 - 10.1
      9.3

      6.3 - 13.1
      5.6

      5.1 - 6.2
      10.4

      8.3 - 12.9
      Reclosure of caesarean wound2.3

      0.7 - 5.3
      Information suppressed because of small cell size (>0 and <5).
      2.7

      1.3 - 4.8
      3.0

      1.4 - 5.5
      1.2

      1.0 - 1.5
      3.4

      2.2 - 4.9
      Caesarean hysterectomy
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      1.9

      0.8 - 3.8
      5.7

      3.4 – 8.9
      3.4

      2.9 – 3.8
      4.8

      3.4 – 6.6
      Hysterectomy – open approach9.0

      5.5 - 14.0
      28.2

      17.0 – 44.0
      5.3

      3.3 - 8.1
      5.1

      3.0 – 8.1
      12.6

      11.8 – 13.5
      6.5

      4.8 8.5
      Puerperal sepsis
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      1.9

      0.8 - 3.8
      1.8

      0.7 - 3.9
      1.9

      1.6 - 2.2
      3.1

      2.0 - 4.6
      Septicemia during labour6.3

      3.5 - 10.6
      10.4

      4.2 - 21.4
      3.9

      2.2 - 6.3
      3.0

      1.4 - 5.5
      6.2

      5.6 - 6.8
      9.1

      7.1 - 11.4
      Obstetric shock
      Information suppressed because of small cell size (>0 and <5).
      0.01.5

      0.5 - 3.2
      3.6

      1.9 - 6.3
      2.9

      2.5 - 3.3
      4.5

      3.1 - 6.2
      Obstetric embolism3.2

      1.3 - 6.5
      Information suppressed because of small cell size (>0 and <5).
      5.3

      3.3 - 8.1
      1.5

      0.5 - 3.5
      3.0

      2.6 - 3.5
      2.0

      1.1 - 3.2
      Disseminated intravascular coagulation
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.6

      0.4 - 0.8
      Information suppressed because of small cell size (>0 and <5).
      Assisted ventilation through endotracheal tube6.8

      3.8 - 11.2
      Information suppressed because of small cell size (>0 and <5).
      4.6

      2.8 - 7.2
      3

      1.4 - 5.5
      7.5

      6.8 - 8.1
      6.2

      4.6 - 8.2
      Assisted ventilation through tracheostomy0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Cardiac complications of anesthesia0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.4

      0.3 - 0.6
      Information suppressed because of small cell size (>0 and <5).
      Cardiomyopathy
      Information suppressed because of small cell size (>0 and <5).
      3.0

      0.4 - 10.7
      2.7

      1.3 - 4.8
      1.5

      0.5 - 3.5
      2.8

      2.4 - 3.2
      1.9

      1.0 - 3.1
      Cardiac arrest and resuscitation
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.9

      0.7 - 1.2
      0.9

      0.3 - 1.8
      Myocardial infraction0.00.00.00.00.1

      0.0 - 0.2
      Information suppressed because of small cell size (>0 and <5).
      Pulmonary edema and heart failure3.2

      1.3 - 6.5
      Information suppressed because of small cell size (>0 and <5).
      3.1

      1.7 - 5.4
      1.5

      0.5 - 3.5
      3.1

      2.7 - 3.6
      3.5

      2.3 - 5.0
      Acute renal failure3.6

      1.6 - 7.1
      Information suppressed because of small cell size (>0 and <5).
      2.2

      1.0 - 4.1
      4.8

      2.7 - 7.8
      3.6

      3.2 - 4.1
      3.1

      2.0 - 4.6
      Dialysis2.3

      0.7 - 5.3
      0.00.00.00.6

      0.5 - 0.9
      Information suppressed because of small cell size (>0 and <5).
      Rupture uterus with red cell transfusion, procedures to uterus or hysterectomy
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      1.2

      0.4 - 2.8
      2.1

      0.8 - 4.3
      1.9

      1.5 - 2.2
      1.9

      1.0 - 3.1
      Cerebral venous thrombosis in pregnancy0.00.0
      Information suppressed because of small cell size (>0 and <5).
      0.00.2

      0.1 - 0.4
      Information suppressed because of small cell size (>0 and <5).
      Cerebral venous thrombosis in the puerperium0.00.00.00.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Cerebrovascular diseases: subarachnoid and intracranial hemorrhage, cerebral infarction, stroke
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.00.8

      0.6 - 1.1
      Information suppressed because of small cell size (>0 and <5).
      Cerebral edema or coma
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Hepatic failure
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.00.3

      0.2 - 0.5
      Information suppressed because of small cell size (>0 and <5).
      Acute fatty liver with red cell transfusion or plasma transfusion2.7

      1.0 - 5.9
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      1.4

      1.1 - 1.7
      0.7

      0.3 - 1.6
      Pulmonary, cardiac, and CNS complications of anaesthesia during pregnancy/labour/delivery/puerperium
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      1.0

      0.8 - 1.2
      1.0

      0.4 - 2.0
      Status asthmaticus
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.00.1

      0.0 - 0.2
      0.6

      0.2 - 1.4
      Adult respiratory distress syndrome
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.00.4

      0.2 - 0.5
      Information suppressed because of small cell size (>0 and <5).
      Acute abdomen
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.7

      0.5 - 0.9
      1.0

      0.4 - 2.0
      Surgical or manual correction of inverted uterus for vaginal births only
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.7

      0.5 - 0.9
      1.1

      0.5 - 2.1
      Sickle cell anemia with crisis0.00.0
      Information suppressed because of small cell size (>0 and <5).
      0.00.7

      0.5 - 0.9
      Information suppressed because of small cell size (>0 and <5).
      Acute psychosis0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.4

      0.2 - 0.5
      Information suppressed because of small cell size (>0 and <5).
      Status epilepticus
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.00.3

      0.2 - 0.5
      Information suppressed because of small cell size (>0 and <5).
      HIV disease
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      1.9

      1.6 - 2.3
      2.7

      1.7 - 4.1
      Severe maternal morbidity subtype/Province or territorySKABBCNTYUNU
      Number of deliveries74,648264,658210,6123,2992,0703,968
      Severe preeclampsia and HELLP syndrome47.7

      42.9 - 52.9
      51.7

      49.0 - 54.5
      58.5

      55.3 - 61.8
      21.2

      8.5 - 43.7
      48.3

      23.2 - 88.7
      65.5

      42.8 - 95.9
      Eclampsia5.5

      3.9 - 7.5
      1.9

      1.4 - 2.5
      4.2

      3.3 - 5.1
      Information suppressed because of small cell size (>0 and <5).
      0.015.1

      5.5 - 32.9
      Placenta previa with hemorrhage with RBC transfusion4.4

      3.0 - 6.2
      2.3

      1.8 - 3.0
      1.3

      0.9 - 1.9
      0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Placental abruption with coagulation defect1.5

      0.7 - 2.6
      1.6

      1.2 - 2.2
      1.1

      0.7 - 1.6
      0.00.00.0
      Antepartum hemorrhage with coagulation defect
      Information suppressed because of small cell size (>0 and <5).
      1.4

      1.0 - 1.9
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.0
      Intrapartum hemorrhage with coagulation defect
      Information suppressed because of small cell size (>0 and <5).
      1.4

      1.0 - 2.0
      0.8

      0.4 - 1.2
      0.00.00.0
      Intrapartum hemorrhage with RBC transfusion3.6

      2.4 - 5.3
      1.3

      0.9 - 1.8
      1.5

      1.0 - 2.1
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Postpartum hemorrhage with RBC transfusion, procedures to the uterus or hysterectomy76.0

      69.9 - 82.4
      34.5

      32.3 - 36.8
      17.5

      15.8 - 19.4
      75.8

      49.1 - 111.7
      106.3

      66.7 - 160.5
      146.2

      111.2 - 188.6
      Curettage with RBC transfusion10.7

      8.5 - 13.3
      3.2

      2.5 - 3.9
      2.1

      1.5 - 2.8
      Information suppressed because of small cell size (>0 and <5).
      33.8

      13.6 - 69.5
      40.3

      23.1 - 65.4
      Maternal ICU admission20.1

      17.0 - 23.6
      14.9

      13.5 - 16.5
      12.7

      11.2 - 14.3
      33.3

      16.7 - 59.6
      29.0

      10.6 - 63.0
      12.6

      4.1 - 29.4
      Complications of obstetric surgery and procedures6.2

      4.5 - 8.2
      11.9

      10.6 - 13.3
      13.0

      11.5 - 14.6
      Information suppressed because of small cell size (>0 and <5).
      53.1

      26.6 - 94.9
      15.1

      5.5 - 32.9
      Evacuation of incisional hematoma with RBC transfusion
      Information suppressed because of small cell size (>0 and <5).
      0.2

      0.1 - 0.5
      0.4

      0.2 - 0.8
      Information suppressed because of small cell size (>0 and <5).
      0.00.0
      Repair of bladder, urethra, or intestine8.2

      6.3 - 10.5
      8.5

      7.5 - 9.7
      9.4

      8.1 - 10.8
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Reclosure of caesarean wound1.9

      1.0 - 3.1
      0.9

      0.6 - 1.4
      0.4

      0.2 - 0.8
      0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Caesarean hysterectomy5.2

      3.7 – 7.1
      3.7

      3.0 – 4.6
      2.8

      2.1 – 3.6
      0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Hysterectomy – open approach7.5

      5.7 – 9.7
      12.6

      11.3 – 14.0
      11.4

      10.0 – 12.9
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Puerperal sepsis2.1

      1.2 - 3.5
      1.4

      1.0 - 1.9
      3.6

      2.8 - 4.5
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Septicemia during labour7.8

      5.9 - 10.0
      6.1

      5.2 - 7.1
      10.8

      9.4 - 12.3
      15.2

      4.9 - 35.3
      33.8

      13.6 - 69.5
      Information suppressed because of small cell size (>0 and <5).
      Obstetric shock4.8

      3.4 - 6.7
      3.3

      2.6 - 4.1
      5.0

      4.1 - 6.1
      0.00.012.6

      4.1 - 29.4
      Obstetric embolism2.8

      1.7 - 4.3
      3.7

      3.0 - 4.5
      2.2

      1.6 - 2.9
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Disseminated intravascular coagulation0.8

      0.3 - 1.8
      1.4

      1.0 - 2.0
      0.9

      0.5 - 1.4
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Assisted ventilation through endotracheal tube8.2

      6.3 - 10.5
      5.4

      4.6 - 6.4
      5.5

      4.5 - 6.6
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Assisted ventilation through tracheostomy
      Information suppressed because of small cell size (>0 and <5).
      0.2

      0.1 - 0.5
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.0
      Cardiac complications of anesthesia0.1

      0.0 - 0.7
      0.3

      0.1 - 0.6
      0.5

      0.2 - 0.9
      Information suppressed because of small cell size (>0 and <5).
      0.00.0
      Cardiomyopathy3.5

      2.3 - 5.1
      2.2

      1.6 - 2.8
      1.9

      1.4 - 2.6
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Cardiac arrest and resuscitation0.7

      0.2 - 1.6
      1.2

      0.8 - 1.7
      1.0

      0.6 - 1.5
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Myocardial infraction
      Information suppressed because of small cell size (>0 and <5).
      0.2

      0.1 - 0.4
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.0
      Pulmonary edema and heart failure3.6

      2.4 - 5.3
      2.6

      2.0 - 3.3
      2.1

      1.5 - 2.8
      0.0
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Acute renal failure3.9

      2.6 - 5.6
      5.3

      4.5 - 6.3
      6.7

      5.7 - 7.9
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.0
      Dialysis0.9

      0.4 - 1.9
      0.3

      0.1 - 0.6
      0.4

      0.2 - 0.8
      0.00.00.0
      Rupture of the uterus with RBC transfusion, procedures to the uterus or hysterectomy2.1

      1.2 - 3.5
      0.5

      0.3 - 0.9
      0.7

      0.4 - 1.2
      Information suppressed because of small cell size (>0 and <5).
      0.00.0
      Cerebral venous thrombosis in pregnancy
      Information suppressed because of small cell size (>0 and <5).
      0.3

      0.2 - 0.6
      0.2

      0.1 - 0.6
      0.00.00.0
      Cerebral venous thrombosis in the puerperium0.0
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.00.0
      Cerebrovascular diseases: subarachnoid and intracranial hemorrhage, cerebral infarction, stroke0.7

      0.2 - 1.6
      0.6

      0.4 - 1.0
      0.5

      0.2 - 0.9
      0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Cerebral edema or coma
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.0
      Hepatic failure
      Information suppressed because of small cell size (>0 and <5).
      Information suppressed because of small cell size (>0 and <5).
      0.2

      0.1 - 0.6
      0.00.00.0
      Acute fatty liver with red blood cell transfusion or plasma transfusion1.9

      1.0 - 3.1
      0.6

      0.4 - 1.0
      0.2

      0.1 - 0.6
      0.00.0
      Information suppressed because of small cell size (>0 and <5).
      Pulmonary, cardiac, and CNS complications of anaesthesia during pregnancy, the puerperium or labour and delivery0.4

      (0.1 - 1.2)
      0.6

      0.3 - 0.9
      2.7

      2.0 - 3.5
      Information suppressed because of small cell size (>0 and <5).
      0.00.0
      Status asthmaticus
      Information suppressed because of small cell size (>0 and <5).
      0.3

      0.1 - 0.5
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.0
      Adult respiratory distress syndrome
      Information suppressed because of small cell size (>0 and <5).
      0.2

      0.1 - 0.5
      0.8

      0.5 - 1.3
      0.00.00.0
      Acute abdomen1.1

      0.5 - 2.1
      1.1

      0.7 - 1.5
      0.9

      0.5 - 1.4
      Information suppressed because of small cell size (>0 and <5).
      0.00.0
      Surgical or manual correction of inverted uterus for vaginal births only1.5

      0.7 - 2.6
      1.1

      0.7 - 1.5
      1.1

      0.7 - 1.6
      Information suppressed because of small cell size (>0 and <5).
      0.012.6

      4.1 - 29.4
      Sickle cell anemia with crisis0.00.2

      0.1 - 0.4
      Information suppressed because of small cell size (>0 and <5).
      0.00.00.0
      Acute psychosis
      Information suppressed because of small cell size (>0 and <5).
      0.2

      0.1 - 0.5
      0.2

      0.1 - 0.6
      0.00.00.0
      Status epilepticus
      Information suppressed because of small cell size (>0 and <5).
      0.3

      0.1 - 0.5
      0.5

      0.3 - 0.9
      0.00.00.0
      HIV disease2.8

      1.7 - 4.3
      2.7

      2.1 - 3.4
      1.0

      0.6 - 1.5
      0.0
      Information suppressed because of small cell size (>0 and <5).
      0.0
      low asterisk Information suppressed because of small cell size (>0 and <5).
      Appendix Table S6Women with eclampsia expressed as a proportion (%) of women with severe pre-eclampsia, HELLP syndrome and eclampsia, provinces/territories Canada (excluding Quebec) 2012-2016
      Severe maternal morbidity type/subtypeNLPENSNBONMB
      Number of deliveries22,1036,74541,32033,460674,68880,514
      Severe preeclampsia and HELLP syndrome110333032593,214378
      Eclampsia1629938856
      Rate of SPE, HELLP and eclampsia57.051.975.580.153.453.9
      Proportion with eclampsia
      Women with eclampsia expressed as a proportion (%) of women with severe pre-eclampsia, HELLP syndrome and eclampsia
      12.75.72.93.410.812.9
      95% CI7.4-19.80.7-19.21.3-5.41.6-6.39.8-11.89.9-16.4
      Rate Ratio1.530.680.340.391.681.59
      95% CI0.96-2.430.18-2.620.18-0.640.21-0.751.45-1.951.23-2.05
      P value0.080.790.00040.004<0.00010.0006
      Severe maternal morbidity type/subtypeSKABBCNTYUNUCanada
      Number of deliveries74,648264,658210,6123,2992,0703,9681,418,085
      Severe preeclampsia and HELLP syndrome3561,3691,232710267,300
      Eclampsia415188
      Information suppressed because of small cell size (>0 and <5).
      06668
      Rate of SPE, HELLP and eclampsia53.253.762.724.248.380.656.2
      Proportion with eclampsia
      Women with eclampsia expressed as a proportion (%) of women with severe pre-eclampsia, HELLP syndrome and eclampsia
      10.33.66.7
      Information suppressed because of small cell size (>0 and <5).
      0.018.88.4
      95% CI7.5-13.82.7-4.75.4-8.2
      Information suppressed because of small cell size (>0 and <5).
      0.0-30.97.2-36.47.8-9.0
      RR1.250.380.76
      Information suppressed because of small cell size (>0 and <5).
      0.002.25-
      95% CI0.93-1.680.29-0.500.62-0.95
      Information suppressed because of small cell size (>0 and <5).
      -1.09-4.65-
      P value0.18<0.00010.020.820.700.04-
      Statistically significant differences indicated by bold text.
      low asterisk Information suppressed because of small cell size (>0 and <5).
      Women with eclampsia expressed as a proportion (%) of women with severe pre-eclampsia, HELLP syndrome and eclampsia

      Surgical Complications

      Surgical complications showed a pattern somewhat similar to that of severe hemorrhage (Figure C, Table 3), although the rate in 2016 was 19% higher than the rate in 2003. Complications of obstetric surgery and procedures increased and then decreased; evacuation of incisional hematoma with red cell transfusion declined steadily; rates of repair of the bladder, urethra, or intestine rose significantly, whereas rates of re-closure of the Caesarean wound with red cell transfusion remained stable (online Appendix Table S2). In 2012-2016, surgical complications were significantly more common in Manitoba, Alberta, British Columbia, and the Yukon and significantly less frequent in Ontario and Saskatchewan (online Appendix Table S4).

      Hysterectomy

      Hysterectomy rates increased between 2003 and 2016 but were stable between 2012 and 2016 (Figure B, Table 3). Caesarean hysterectomy increased, whereas hysterectomy for postpartum hemorrhage by the open approach remained stable (online Appendix Table S2). Hysterectomy rates were significantly higher in Prince Edward Island, Ontario, and Alberta and significantly lower in Nova Scotia, New Brunswick, and Manitoba than in the rest of Canada (online Appendix Table S4).

      Sepsis

      Sepsis rates declined significantly (Figure A, Table 3); the puerperal sepsis subtype declined substantially, whereas septicemia in labour remained stable (online Appendix Table S2). Sepsis rates in 2012-2016 were significantly higher in Manitoba, British Columbia, and the Yukon and significantly lower in Nova Scotia, New Brunswick, Ontario, and Alberta compared with the rest of Canada (online Appendix Table S4).

      Embolism, Shock, and Disseminated Intravascular Coagulation

      Rates of obstetric embolism, shock, and DIC increased; stratified analyses showed that obstetric embolism and obstetric shock increased significantly, whereas DIC rates did not change. The rate of this SMM type in 2012-2016 was significantly higher in Alberta, British Columbia, and Nunavut and significantly lower in Ontario.

      Assisted Ventilation

      Rates of assisted ventilation increased (Figure D, Table 3). Rates of assisted ventilation were significantly lower in New Brunswick and Alberta than in the rest of Canada (online Appendix Table S4).

      Cardiac Conditions

      Rates of cardiac conditions remained unchanged overall. Cardiac SMM subtypes, such as cardiomyopathy, rose significantly over the 14 years, whereas pulmonary edema and heart failure rates declined significantly, and the frequency of cardiac complications of anaesthesia, cardiac arrest and resuscitation, and myocardial infarction remained unchanged (online Appendix Table S2). The frequency of cardiac conditions was significantly higher in Ontario and Nunavut and significantly lower in British Columbia in 2012-2016 (online Appendix Table S4).

      Acute Renal Failure

      Acute renal failure and dialysis increased substantially (Figure D, Table 3). Rates in 2012-2016 were significantly higher in Alberta and British Columbia and significantly lower in Nova Scotia and Ontario compared with the rest of Canada (online Appendix Table S4).

      Severe Uterine Rupture

      Severe uterine rupture showed a small and increasing temporal trend (Figure C, Table 3). Rates of severe uterine rupture in 2012-2016 were significantly higher in Ontario than in the rest of Canada and significantly lower in Alberta and British Columbia (online Appendix Table S4).

      Cerebrovascular Accidents

      Cerebrovascular accidents increased, and two subtypes (stroke and cerebral venous thrombosis in pregnancy) showed a significant temporal increase (online Appendix Table S2). Stroke rates in 2012-2016 showed no significant regional variation.

      Miscellaneous Severe Maternal Morbidity

      Acute fatty liver with red cell or plasma transfusion, sickle cell crisis, status epilepticus, and human immunodeficiency virus infection showed significant increases from 2003 to 2016, whereas status asthmaticus, adult respiratory distress syndrome, surgical or manual correction of an inverted uterus, and acute psychosis showed a significant decline (online Appendix Table S2). Rates of surgical or manual correction of an inverted uterus were unexpectedly high in Nunavut in 2012-2016.

      DISCUSSION

      Our study provides a comprehensive overview of temporal trends and regional variations in SMM in Canada (excluding Québec) from 2012 to 2016 and temporal trends in SMM from 2003 to 2016. The results include a sequential rise and fall in rates of severe hemorrhage and surgical complications over the 14-year period. Because severe hemorrhage was one of the most common SMM types, the recent reduction in this severe morbidity resulted in a temporal reduction in composite SMM between 2012 and 2016. Stroke, severe uterine rupture, embolism, shock and DIC, acute renal failure, hysterectomy, surgical complications, and assisted ventilation rates rose significantly between 2003 and 2016; rates of cardiac conditions were stable; and sepsis and maternal ICU admission rates declined significantly. Some of the changes in SMM types concealed disparate changes in component subtypes. Thus, the stability in overall cardiac conditions between 2003 and 2016 obscured rising rates of cardiomyopathy and declining rates of pulmonary edema and heart failure. Interprovincial and territorial comparisons showed significant differences in rates of composite SMM and SMM types and subtypes and suggested regional priorities for clinical and public health initiatives.
      The diverse SMM trends and regional variations presented in this paper require careful study. A brief discussion of some important findings is attempted here, with a more detailed discussion provided in the online Appendix. Rates of eclampsia in Canada
      • Liu S
      • Joseph KS
      • Liston RM
      • et al.
      Incidence, risk factors, and associated complications of eclampsia.
      declined in a nearly monotonic pattern to 5.3 per 10 000 deliveries in 2016 (online Appendix Table S2). These rates were similar to the 5.6 per 10 000 reported in the United Kingdom in 2012-2013,
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      6.2 per 10 000 in the Netherlands in 2004-2006,
      • Zwart JJ
      • Richters JM
      • Ory F
      • et al.
      Severe maternal morbidity during pregnancy, delivery and puerperium in the Netherlands: a nationwide population-based study of 371,000 pregnancies.
      and 6.6 per 10 000 in the United States in 2014.
      • Kuklina EV
      • Goodman DA
      Severe maternal or near miss morbidity: implications for public health surveillance and clinical audit.
      • Fingar KR
      • Mabry-Hernandez I
      • Ngo-Metzger Q
      • et al.
      Delivery hospitalizations involving preeclampsia and eclampsia, 2005–2014: statistical brief #222. Healthcare Cost and Utilization Project (HCUP) Statistical Briefs [Internet].
      The recent rise in rates of postpartum hemorrhage and severe postpartum hemorrhage in Canada and other high-income countries has been well documented,
      • Cameron CA
      • Roberts CL
      • Olive EC
      • et al.
      Trends in postpartum hemorrhage.
      • Ford JB
      • Roberts CL
      • Simpson JM
      • et al.
      Increased postpartum hemorrhage rates in Australia.
      • Joseph KS
      • Rouleau J
      • Kramer MS
      • et al.
      Investigation of an increase in postpartum hemorrhage in Canada.
      • Knight M
      • Callaghan WM
      • Berg C
      • et al.
      Trends in postpartum hemorrhage in high resource countries: a review and recommendations from the International Postpartum Hemorrhage Collaborative Group.
      • Callaghan WM
      • Kuklina EV
      • Berg CJ
      Trends in postpartum hemorrhage: United States, 1994-2006.
      • Kramer MS
      • Dahhou M
      • Vallerand D
      • et al.
      Risk factors for postpartum hemorrhage: can we explain the recent temporal increase?.
      • Lutomski JE
      • Byrne BM
      • Devane D
      • et al.
      Increasing trends in atonic postpartum hemorrhage in Ireland: an 11-year population based cohort study.
      • Kramer MS
      • Berg C
      • Abenhaim H
      • et al.
      Incidence, risk factors, and temporal trends in severe postpartum hemorrhage.
      • Mehrabadi A
      • Hutcheon JA
      • Lee L
      • et al.
      Epidemiological investigation of a temporal increase in atonic postpartum hemorrhage: a population-based retrospective cohort study.
      • Mehrabadi A
      • Liu SL
      • Bartholomew S
      • et al.
      Temporal trends in postpartum hemorrhage and severe postpartum hemorrhage in Canada from 2003 to 2010.
      although epidemiologic investigations have failed to pinpoint a cause. The more recent fall in severe postpartum hemorrhage rates since 2012 is a welcome development, although the cause of this decline is equally unclear. Detailed studies are required to examine possible causes for the decline, including the increased use of tranexamic acid,
      World Health Organization (WHO)
      Recommendations for the prevention and treatment of postpartum haemorrhage.
      because the potential for prevention is evident in the widely varying regional rates of severe hemorrhage.
      Increases in rates of repair of the bladder, urethra, and intestine are concerning. Bladder and intestinal injuries may be related to the increase in Caesarean deliveries and in deliveries to women with a previous Caesarean section, whereas injuries to the urethra may be a consequence of the restricted use of episiotomy.
      • Hong J
      • Qian X
      • Carroli G
      • et al.
      Selective versus routine use of episiotomy for vaginal birth.
      Obstetric embolism rates in 2012 and 2013 in Canada (excluding Québec) of 2.9 and 3.0 per 10 000 deliveries were similar to those reported from the United Kingdom in the same years (2.7 per 10 000 deliveries
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      ) and from Australia in 2009 (3.9 per 10 000 deliveries
      • Roberts C
      • Ford J
      • Algert C
      • et al.
      Trends in adverse maternal outcomes during childbirth: a population-based study of severe maternal morbidity.
      ).
      The temporal frequency of acute renal failure and dialysis increased markedly. This adverse trend has been noted previously,
      • Mehrabadi A
      • Liu S
      • Bartholomew S
      • et al.
      Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study.
      and it has been shown to be restricted to women with preeclampsia and other hypertensive disorders of pregnancy. The rise is likely the result of fluid management protocols for women with preeclampsia. Curtailment of fluid intake in an attempt to prevent pulmonary edema may be increasing the risk of acute renal failure in some Canadian jurisdictions.
      • Mehrabadi A
      • Liu S
      • Bartholomew S
      • et al.
      Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study.
      In support of that explanation, provinces with relatively high rates of acute renal failure in 2012-2016 (i.e., Alberta and British Columbia) also had relatively low rates of pulmonary edema and heart failure (online Appendix Table S5).
      Other concerning trends include the temporal increase in cardiomyopathy (which may be related to increases in substance abuse and obesity
      • Hameed AB
      • Lawton ES
      • McCain CL
      • et al.
      Pregnancy-related cardiovascular deaths in California: beyond peripartum cardiomyopathy.
      ), severe uterine rupture, and cerebrovascular accidents. The rising trend in severe uterine rupture noted in this study does not appear to be related to increases in attempted vaginal birth after Caesarean section (VBAC; which decreased from 34.0% in 2003 to 31.4% in 2014).
      • Young CB
      • Liu S
      • Muraca GM
      • et al.
      Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity.
      Rather, the rise may have been related to changes in the selection of candidates for attempted VBAC or changes in the expertise of health care providers because severe neonatal complications following attempted VBAC also increased over the study period.
      • Young CB
      • Liu S
      • Muraca GM
      • et al.
      Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity.
      Finally, the rise in cerebrovascular accidents appears to be unrelated to increases in maternal age. A recent study by the Canadian Perinatal Surveillance System showed that most strokes occurred in the postpartum period and were strongly associated with hypertensive disorders of pregnancy,
      • Liu S
      • Chan W-S
      • Ray JG
      • et al.
      Stroke and cerebrovascular disease in pregnancy: incidence, temporal trends, and risk factors.
      a finding indicating a need for improved management of hypertensive disorders, especially in the postpartum period.
      The strengths of our study include the comprehensive assessment of SMM by using a validated data source. Detailed temporal and regional comparisons provide information to guide clinicians and policy experts in identifying priority issues. Limitations of our study include shortcomings in the framework for SMM surveillance, which was based on ICD-10CA and CCI codes, and this may have failed to identify some SMM cases accurately. Our inability to include information from the province of Québec (which does not contribute to the Discharge Abstract Database) was another significant limitation of our study.

      CONCLUSION

      Health care providers and public health managers in the perinatal domain can use the evidence from our overview to improve quality of care and maternal health. Provinces and territories with high rates of specific SMM types and subtypes (e.g., severe hemorrhage, acute renal failure, sepsis, and surgical complication rates) should target these conditions with quality improvement initiatives. Similarly, increases in severe uterine rupture, obstetric embolism, and shock should be highlighted and addressed through appropriate changes in obstetric management. Finally, our report should stimulate future research to elucidate the causes underlying the temporal changes and regional differences we observed (i.e., the responsible maternal characteristics, clinical management, and health system factors).

      Supplementary data

      Supplementary data related to this article can be found at https://10.1016/j.jogc.2019.02.014.

      Appendix

      Detailed discussion of temporal trends and regional variations

      Severe pre-eclampsia, HELLP syndrome and eclampsia: This relatively common SMM type showed no temporal trend between 2012 and 2016. Eclampsia is preventable, and geographic variations can serve as a marker of differences in the availability and/or quality of obstetric services. Absolute rates of eclampsia in Canada [
      • Liu S
      • Joseph KS
      • Liston RM
      • et al.
      Incidence, risk factors, and associated complications of eclampsia.
      ] showed a near-monotonic decline from 12.4 in 2003 to a low of 4.0 in 2015 and 5.3 per 10,000 deliveries in 2016 (Appendix Table S2). Those rates were similar to the 5.6 per 10,000 reported in the United Kingdom in 2012-13 [
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      ], 6.2 per 10,000 in the Netherlands in 2004-06 [
      • Zwart JJ
      • Richters JM
      • Ory F
      • et al.
      Severe maternal morbidity during pregnancy, delivery and puerperium in the Netherlands: a nationwide population-based study of 371,000 pregnancies.
      ], and 6.6 per 10,000 in the United States in 2014 (based on ICD-9 codes [
      • Kuklina EV
      • Goodman DA
      Severe maternal or near miss morbidity: implications for public health surveillance and clinical audit.
      ,
      • Fingar KR
      • Mabry-Hernandez I
      • Ngo-Metzger Q
      • et al.
      Delivery hospitalizations involving preeclampsia and eclampsia, 2005–2014: statistical brief #222. Healthcare Cost and Utilization Project (HCUP) Statistical Briefs [Internet].
      ]). Within Canada, eclampsia rates were highest in Nunavut (15.1, 95% CI 5.5-32.9 per 10,000 deliveries) in 2012-2016.
      Severe hemorrhage: The recent rise in rates of postpartum hemorrhage and severe postpartum hemorrhage in Canada and other high-income countries has been well documented [
      • Cameron CA
      • Roberts CL
      • Olive EC
      • et al.
      Trends in postpartum hemorrhage.
      ,
      • Ford JB
      • Roberts CL
      • Simpson JM
      • et al.
      Increased postpartum hemorrhage rates in Australia.
      ,
      • Joseph KS
      • Rouleau J
      • Kramer MS
      • et al.
      Investigation of an increase in postpartum hemorrhage in Canada.
      ,
      • Knight M
      • Callaghan WM
      • Berg C
      • et al.
      Trends in postpartum hemorrhage in high resource countries: a review and recommendations from the International Postpartum Hemorrhage Collaborative Group.
      ,
      • Callaghan WM
      • Kuklina EV
      • Berg CJ
      Trends in postpartum hemorrhage: United States, 1994-2006.
      ,
      • Kramer MS
      • Dahhou M
      • Vallerand D
      • et al.
      Risk factors for postpartum hemorrhage: can we explain the recent temporal increase?.
      ,
      • Lutomski JE
      • Byrne BM
      • Devane D
      • et al.
      Increasing trends in atonic postpartum hemorrhage in Ireland: an 11-year population based cohort study.
      ,
      • Kramer MS
      • Berg C
      • Abenhaim H
      • et al.
      Incidence, risk factors, and temporal trends in severe postpartum hemorrhage.
      ,
      • Mehrabadi A
      • Hutcheon JA
      • Lee L
      • et al.
      Epidemiological investigation of a temporal increase in atonic postpartum hemorrhage: a population-based retrospective cohort study.
      ,
      • Mehrabadi A
      • Liu SL
      • Bartholomew S
      • et al.
      Temporal trends in postpartum hemorrhage and severe postpartum hemorrhage in Canada from 2003 to 2010.
      ], although epidemiologic investigations have failed to pinpoint a cause. The more recent fall in severe postpartum hemorrhage rates since 2012 is a welcome development, although the cause of this decline is equally unclear. Despite its decline since 2012, severe hemorrhage represents one of the most common types of SMM in Canada. Its potential for prevention is evident in the widely varying rates by province and territory: significantly higher in Newfoundland and Labrador, Nova Scotia, New Brunswick, Ontario, Manitoba, Saskatchewan and the 3 territories than in the rest of Canada.
      ICU admission: Maternal admissions to ICU declined from 24.1 to 19.8 per 10,000 deliveries in 2003 vs 2016. The rate in 2003 was similar to the 24 per 10,000 deliveries reported in the Netherlands in 2004-2006 [
      • Zwart JJ
      • Richters JM
      • Ory F
      • et al.
      Severe maternal morbidity during pregnancy, delivery and puerperium in the Netherlands: a nationwide population-based study of 371,000 pregnancies.
      ]. The observed interprovincial differences in rates of ICU admission may be due to the introduction of step-down units (which deliver a lower intensity of care than traditional ICUs) in some provinces.
      Surgical complications: The rise and fall in this SMM type reflects the trend in its most common subtype: complications of obstetric surgery and procedures (ICD-10CA code O75.4). The latter subtype is heterogeneous (comprising cardiac arrest, cardiac failure or cerebral anoxia following caesarean delivery or other obstetric surgery or procedures, including delivery not otherwise specified, and also post-procedural renal failure and post-procedural disorders of the genitourinary system), thus clouding interpretation. Increases in rates of repair of the bladder, urethra and intestine are concerning, while reduction in rates of incisional hematoma requiring evacuation and transfusion are encouraging. Provinces/territories with higher rates of surgical complications included Manitoba, Alberta, British Columbia and the Yukon.
      Hysterectomy: Rates of hysterectomy showed a significant rise, with a rate of 15.8 per 10,000 deliveries in 2016. Rates reported elsewhere were 2.2 in the United Kingdom in 2012-13 [
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      ] and 10.7 per 10,000 deliveries in the United States in 2014 [
      • Kuklina EV
      • Goodman DA
      Severe maternal or near miss morbidity: implications for public health surveillance and clinical audit.
      ]. Within Canada, Prince Edward Island, Ontario and Alberta had significantly higher rates than the rest of Canada. British Columbia, previously reported to have low rates of postpartum hemorrhage with blood transfusion and high rates of hysterectomy in 2003 to 2007 [
      • Liu S
      • Joseph KS
      • Bartholomew S
      • et al.
      Temporal trends and regional variations in severe maternal morbidity in Canada, 2003 to 2007.
      ], had relatively low rates of severe hemorrhage but rates of hysterectomy that were similar to those in the rest of Canada in 2012-2016.
      Sepsis: Rates of sepsis continued the steady decline from previous years and likely reflect the antiseptic techniques and antibiotic prophylaxis regimens instituted in recent decades. However, rates of sepsis were significantly higher in Manitoba, British Columbia and the Yukon than in the rest of Canada. Sepsis rates of 9.0 and 9.3 per 10,000 deliveries in Canada in 2012 and 2013 were similar to sepsis rates of 10.3 in the United Kingdom in the same years [
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      ], but the Canadian rate of 8.5 in 2016 was higher than the rate of 6.8 per 10,000 deliveries reported in the United States two years earlier [
      • Kuklina EV
      • Goodman DA
      Severe maternal or near miss morbidity: implications for public health surveillance and clinical audit.
      ].
      Embolism, shock and DIC: Rates of obstetric embolism and shock rose significantly from 2003 to 2016, with the trend continuing in the most recent 5 years. Rates were significantly higher in Alberta, British Columbia and Nunavut compared with the rest of Canada. Obstetric embolism rates in 2012 and 2013 in Canada (excluding Quebec) of 2.9 and 3.0 per 10,000 deliveries were similar to those reported from the United Kingdom in those years (2.7 per 10,000 deliveries [
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      ]) and from Australia (3.9 per 10,000 deliveries [
      • Roberts C
      • Ford J
      • Algert C
      • et al.
      Trends in adverse maternal outcomes during childbirth: a population-based study of severe maternal morbidity.
      ]).
      Acute renal failure: Rates of acute renal failure and dialysis increased markedly from 1.7 to 5.9 per 10,000 deliveries in 2003 vs 2016 in Canada and rates were significantly higher in Alberta and British Columbia compared with the rest of Canada. This adverse trend has been noted previously [
      • Mehrabadi A
      • Liu S
      • Bartholomew S
      • et al.
      Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study.
      ] and shown to be restricted to women with pre-eclampsia and other hypertensive disorders of pregnancy. The rise is likely due to fluid management protocols for women with pre-eclampsia. Curtailment of fluid intake in an attempt to prevent pulmonary edema may be increasing the risk of acute renal failure in some Canadian jurisdictions [
      • Mehrabadi A
      • Liu S
      • Bartholomew S
      • et al.
      Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study.
      ]. In support of that explanation, provinces with relatively high rates of acute renal failure in 2012-2016 (viz., Alberta and British Columbia) also had relatively low rates of pulmonary edema and heart failure (Appendix Table S5).
      Cardiac conditions: Cardiac conditions have a high case fatality (40.6 per 1000 in 2012-16 [Dzakpasu S, Deb-Rinker P, Arbour L, et al. Severe maternal morbidity surveillance: monitoring pregnant women at high risk for prolonged hospitalization and death [submitted for publication]]), with the highest death rates occurring among those with cardiac arrest and resuscitation. This latter SMM subtype represents the terminal event of many heterogeneous pathologic processes; fortunately, its frequency is low. The observed temporal increase in cardiomyopathy is concerning, given its high mortality, and may be related to increases in substance abuse and obesity [
      • Hameed AB
      • Lawton ES
      • McCain CL
      • et al.
      Pregnancy-related cardiovascular deaths in California: beyond peripartum cardiomyopathy.
      ].
      Assisted ventilation: Rates of assisted ventilation increased substantially, although no province/territory has significantly higher rates than the rest of Canada. Assisted ventilation rates of 7.2 per 10,000 deliveries in Canada in 2016 were higher than the 2.6 per 10,000 reported in the United Kingdom in 2012-2013 [
      • Nair M
      • Kurinczuk JJ
      • Knight M
      Establishing a national maternal morbidity outcome indicator in England: a population-based study using routine hospital data.
      ] but similar to the 7.8 per 10,000 reported in the United States in 2014 [
      • Kuklina EV
      • Goodman DA
      Severe maternal or near miss morbidity: implications for public health surveillance and clinical audit.
      ].
      Severe uterine rupture: Rates of uterine rupture associated with red cell transfusion, procedures to the uterus or hysterectomy were relatively rare but showed a significant rise between 2003 and 2016. Uterine rupture is strongly associated with attempted vaginal birth after caesarean delivery (VBAC), but the rising trend in severe uterine rupture noted in this study does not appear to be related to increases in attempted VBAC (which decreased from 34.0% in 2003 to 31.4% in 2014 [
      • Young CB
      • Liu S
      • Muraca GM
      • et al.
      Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity.
      ]). Rather, the rise may have been related to changes in selection of candidates for attempted VBAC and/or changes in the expertise of health care providers [
      • Young CB
      • Liu S
      • Muraca GM
      • et al.
      Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity.
      ]. This speculation is supported by the fact that severe neonatal complications of attempted VBAC increased over the study period (adjusted rate ratios for neonatal mortality and severe neonatal morbidity associated with attempted VBAC compared with elective repeat caesarean increased from 0.94, 95% CI 0.77-1.15 in 2003-05 to 2.07, 95% CI 1.83-2.35 in 2012-14 [
      • Young CB
      • Liu S
      • Muraca GM
      • et al.
      Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity.
      ]).
      Cerebrovascular accidents: The rates of cerebrovascular accidents and of cerebral thrombosis in pregnancy have increased, especially in recent years. A recent study by the Canadian Perinatal Surveillance System showed that adjustment for maternal age did not abolish the temporal rise in stroke rates [
      • Liu S
      • Chan W-S
      • Ray JG
      • et al.
      Stroke and cerebrovascular disease in pregnancy: incidence, temporal trends, and risk factors.
      ]. Most strokes occurred in the postpartum period and were strongly associated with hypertensive disorders of pregnancy [
      • Liu S
      • Chan W-S
      • Ray JG
      • et al.
      Stroke and cerebrovascular disease in pregnancy: incidence, temporal trends, and risk factors.
      ], indicating a need for improved management of hypertensive disorders, especially in the postpartum period.

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