Abstract
Objectives
• To assess the association between sonography-derived cervical length measurement
and preterm birth.
• To describe the various techniques to measure cervical length using sonography.
• To review the natural history of the short cervix.
• To review the clinical uses, predictive ability, and utility of sonography-measured
short cervix.
Outcomes
Reduction in rates of prematurity and/or better identification of those at risk, as
well as possible prevention of unnecessary interventions.
Intended Users
Clinicians involved in the obstetrical management or cervical imaging of patients
at increased risk of a short cervix.
Target Population
Women at increased risk of a short cervix or at risk of preterm birth.
Evidence
Literature published up to June 2019 was retrieved through searches of PubMed and
the Cochrane Library using appropriate controlled vocabulary and key words (preterm
labour, ultrasound, cervix, cervical insufficiency, transvaginal, transperineal, cervical
length, fibronectin). Results were restricted to general and systematic reviews, randomized
controlled trials, controlled clinical trials, and observational studies. There were
no date or language restrictions. Grey (unpublished) literature was identified through
searching the websites of health technology assessment agencies, clinical practice
guideline collections, clinical trial registries, and national and international medical
specialty societies.
Values
The evidence and this guideline were reviewed by the Diagnostic Imaging Committee
of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations
were made and graded according to the rankings of the Canadian Task Force on Preventive
Health Care (Online Appendix Table A1).
Benefits, Harms, Costs
Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the
sonographic technique reviewed in this guideline may help identify women at risk of
preterm birth and, in some circumstances, lead to interventions that may reduce the
rate of preterm birth.
SUMMARY STATEMENTS (Canadian Task Force on Preventive Health Care grading in parentheses)
- 1In the general obstetrical population, cervical length is relatively stable over the first 2 trimesters. The natural history of cervical length change may not be useful in identifying women at increased risk of spontaneous preterm birth. Because there may be different patterns, rates, and/or onset of cervical length shortening, repeat assessment of cervical length may be useful in patients at high risk of spontaneous preterm birth (II-2).
- 2Transvaginal sonography can be used to assess the risk of preterm birth in women with a history of spontaneous preterm birth and to differentiate those at higher and lower risk of preterm delivery (II-2).
- 3Cervical length measurement can be used to identify those at increased risk of preterm birth in asymptomatic women at <24 weeks gestation who have other risk factors for preterm birth (uterine anomaly or prior multiple dilatation and evacuation procedures beyond 13 weeks gestation). However, there is insufficient evidence to recommend specific management strategies in this group of women (II-2).
- 4There is no consensus on the optimal timing or frequency of serial evaluations of cervical length. If repeat measurements are performed, they should be done at suitable intervals to minimize the likelihood of observation error (II-2).
- 5No specific randomized trials have evaluated any interventions in asymptomatic women initially diagnosed at or beyond 24 weeks gestation who are at increased risk of preterm birth (e.g., those who have a history of prior spontaneous preterm birth, uterine anomaly, or prior multiple dilatation and evacuation procedures beyond 13 weeks gestation) and who have a short cervical length. However, knowledge of cervicanalal length beyond 24 weeks may help with empiric management strategies for these women, such as relocation and increased surveillance (III).
- 6In women presenting with suspected preterm labour and intact membranes, transvaginal sonographic assessment of cervical length may be used to help stratify the risk of preterm delivery and prevent unnecessary intervention without harm. This information may result in a reduction in late preterm birth, but it is unclear whether it makes a significant clinical difference (II-2B).
- 7Cervical length surveillance is a safe option for patients with a prior sonography indicated cerclage, unclear history of cervical insufficiency, and prior spontaneous preterm birth when compared with routine cerclage based on clinical assessment; it may reduce the need for subsequent cerclage (II-2B).
- 8Transvaginal sonography appears to be safe in preterm prelabour rupture of membranes, but its clinical predictive value is uncertain in this context (II-2).
- 9There is insufficient evidence to support a committee position on the frequency or timing of sonographic cervical length assessment post cerclage. It is unclear if there is significant clinical benefit of such scans (III).
- 10Sonographic cervical length assessment and fetal fibronectin appear to be similar in predictive ability in symptomatic patients, and their combined value may not be significantly different from assessment of cervical length alone. More research is needed in this area (II-2).
RECOMMENDATIONS (Canadian Task Force on Preventive Health Care grading in parentheses)
- 1Transvaginal sonography is the preferred approach for cervical assessment to identify women at increased risk of spontaneous preterm birth, and it can be offered to women at increased risk of preterm birth (II-2B).
- 2Transperineal sonography can be offered to women at increased risk of preterm birth if transvaginal sonography is either unacceptable or unavailable (II-2B). Transabdominal assessment of cervical length may be a useful alternative for screening under certain conditions.
Keywords
Abbreviations:
LEEP (loop electrosurgical excision procedure), PPROM (preterm premature rupture of membranes)To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Journal of Obstetrics and Gynaecology CanadaAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
REFERENCES
Institute of Medicine Committee on Understanding Premature Birth, Assuring Healthy Outcomes. The National Academies Collection: Reports funded by National Institutes of Health. In: Behrman RE, Butler AS, editors. Preterm Birth: Causes, Consequences, and Prevention. Washington (DC): National Academies Press: 2007
- 4 million neonatal deaths: when? Where? Why?.Lancet. 2005; 365 (Available from:): 891-900
- Determinants of preterm birth rates in Canada from 1981 through 1983 and from 1992 through 1994.N Engl J Med. 1998; 339 (Available from:): 1434-1439
- Pregnancy outcomes after assisted reproductive technology.J Obstet Gynaecol Can. 2006; 28 (Available from:): 220-233
- Magnesium sulphate for preventing preterm birth in threatened preterm labour.Cochrane Database Syst Rev. 2002; (Available from:)CD001060
- Betamimetics for inhibiting preterm labour.Cochrane Database Syst Rev. 2004; (Available from:)CD004352
- Oxytocin receptor antagonists for inhibiting preterm labour.Cochrane Database Syst Rev. 2005; (Available from:)CD004452
- Nifedipine and ritodrine in the management of preterm labor: a randomized multicenter trial.Obstet Gynecol. 1997; 90 (Available from:): 230-234
- Nitric oxide donors for the treatment of preterm labour.Cochrane Database Syst Rev. 2002; (Available from:)CD002860
- Randomized double-blind placebo-controlled trial of transdermal nitroglycerin for preterm labor.Am J Obstet Gynecol. 2007; 196 (Available from:): 37 e1-8
- Assessing the neonatal safety of indomethacin tocolysis: a systematic review with meta-analysis.Obstet Gynecol. 2005; 106 (Available from:): 173-179
- Cyclo-oxygenase (COX) inhibitors for treating preterm labour.Cochrane Database Syst Rev. 2005; (Available from:)CD001992
- Calcium channel blockers for inhibiting preterm labour.Cochrane Database Syst Rev. 2003; (Available from:)CD002255
- Ultrasonographic cervical length assessment in predicting preterm birth in singleton pregnancies.J Obstet Gynaecol Can. 2011; 33: 486-499
- No. 373-Cervical Insufficiency and Cervical Cerclage.J Obstet Gynaecol Can. 2019; 41 (Available from:): 233-247
- No. 374-Universal Cervical Length Screening.J Obstet Gynaecol Can. 2019; 41 (Available from:): 363-74 e1
- Guideline No. 398: Progesterone for Prevention of Spontaneous Preterm Birth.J Obstet Gynaecol Can. 2020; 42: 806-812
- Uterine contractions in asymptomatic pregnant women with a short cervix on ultrasound.J Matern Fetal Neonatal Med. 2005; 18 (Available from:): 325-328
- Frequency of uterine contractions in asymptomatic pregnant women with or without a short cervix on transvaginal ultrasound scan.Am J Obstet Gynecol. 2004; 191 (Available from:): 1253-1256
What are the risk factors for preterm labor and birth? Eunice Kennedy Shriver National Institute of Child Health and Human Development, US Deaprtment of health and Human Services. Available from: https://www.nichd.nih.gov/health/topics/preterm/conditioninfo/who_risk.
- Preterm birth: Risk factors, interventions for risk reduction, and maternal prognosis.UpToDate. 2019; (Available from:)
- The Preterm Prediction Study: toward a multiple-marker test for spontaneous preterm birth.Am J Obstet Gynecol. 2001; 185 (Available from:): 643-651
- Markers of risk for preterm delivery.J Perinat Med. 1999; 27 (Available from:): 5-20
- Cervical length and prediction of preterm delivery.Curr Opin Obstet Gynecol. 2007; 19 (Available from:): 191-195
- The length of the cervix and the risk of spontaneous premature delivery. National Institute of Child Health and Human Development Maternal Fetal Medicine Unit Network.N Engl J Med. 1996; 334 (Available from:): 567-572
- Evaluation and validation of a new risk score (CLEOPATRA score) to predict the probability of premature delivery for patients with threatened preterm labor.Ultrasound Obstet Gynecol. 2005; 26 (Available from:): 699-706
- Accuracy of cervical transvaginal sonography in predicting preterm birth: a systematic review.Ultrasound Obstet Gynecol. 2003; 22 (Available from:): 305-322
- Prediction and early detection of preterm labor.Obstet Gynecol. 2003; 101 (Available from:): 402-412
- A systematic review and quality assessment of systematic reviews of fetal fibronectin and transvaginal length for predicting preterm birth.Eur J Obstet Gynecol Reprod Biol. 2007; 133 (Available from:): 134-142
- Transvaginal ultrasonography examination of the uterine cervix in hospitalised women undergoing preterm labour.Eur J Obstet Gynecol Reprod Biol. 2000; 90 (Available from:): 3-11
- The preterm prediction study: the value of new vs standard risk factors in predicting early and all spontaneous preterm births.NICHD MFMU Network. Am J Public Health. 1998; 88 (Available from:): 233-238
- Accuracy of cervicovaginal fetal fibronectin test in predicting risk of spontaneous preterm birth: systematic review.BMJ. 2002; 325 (Available from:): 301
- Fetal fibronectin–how useful is it in the prediction of preterm birth?.BJOG. 2003; 110 (Available from:): 66-70
- The evaluation of the fetal fibronectin test for prediction of preterm delivery in symptomatic patients.J Obstet Gynaecol Can. 2006; 28 (Available from:): 206-213
- Best practice in maternal-fetal medicine.Int J Gynaecol Obstet. 2015; 128 (Available from:): 80-82
- Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data.Am J Obstet Gynecol. 2018; 218 (Available from:): 161-180
- Cerclage for short cervix on ultrasonography in women with singleton gestations and previous preterm birth: a meta-analysis.Obstet Gynecol. 2011; 117 (Available from:): 663-671
- Cervical insufficiency and cervical cerclage.J Obstet Gynaecol Can. 2013; 35 (Available from:): 1115-1127
- Cerclage for sonographic short cervix in singleton gestations without prior spontaneous preterm birth: systematic review and meta-analysis of randomized controlled trials using individual patient-level data.Ultrasound Obstet Gynecol. 2017; 50 (Available from:): 569-577
- Effect of Cervical Pessary on Spontaneous Preterm Birth in Women With Singleton Pregnancies and Short Cervical Length: A Randomized Clinical Trial.JAMA. 2017; 318 (Available from:): 2317-2324
The Society for Maternal-Fetal Medicine. CLEAR - Cervical Length Education and Review. 2018. Available from:https://clear.perinatalquality.org.
The Fetal Medicine Foundation. Certificate of Competence in Carvical Assessment. 2018. Available from: https://fetalmedicine.org/fmf-certification/certificates-of-competence/cervical-assessment-1.
The Fetal Medicine Foundation F. Cervical assessment. Available from: https://fetalmedicine.org/fmf-certification/certificates-of-competence/cervical-assessment-1.
- A comparison of ultrasonographically detected cervical changes in response to transfundal pressure, coughing, and standing in predicting cervical incompetence.Am J Obstet Gynecol. 1997; 177 (Available from:): 660-665
- A comparison of cervical length measurement techniques for the prediction of spontaneous preterm birth.J Matern Fetal Neonatal Med. 2017; 30 (Available from:): 50-53
- Cervical assessment at the routine 23-week scan: standardizing techniques.Ultrasound Obstet Gynecol. 2001; 17 (Available from:): 217-219
- The role of routine cervical length screening in selected high- and low-risk women for preterm birth prevention.Am J Obstet Gynecol. 2016; 215 (Available from:): B2-B7
- Practice bulletin no. 130: prediction and prevention of preterm birth.Obstet Gynecol. 2012; 120 (Available from:): 964-973
- Reducing preterm birth by a statewide multifaceted program: an implementation study.Am J Obstet Gynecol. 2017; 216 (Available from:): 434-442
- Is transabdominal sonography of the cervix after voiding a reliable method of cervical length assessment?.J Ultrasound Med. 2008; 27 (Available from:): 1305-1311
- Can transabdominal ultrasound identify women at high risk for short cervical length?.Acta Obstet Gynecol Scand. 2013; 92 (Available from:): 637-641
- Prediction of cervical cerclage outcome by endovaginal ultrasonography.Am J Obstet Gynecol. 1994; 171 (Available from:): 1102-1106
- Cervical assessment at the routine 23-weeks' scan: problems with transabdominal sonography.Ultrasound Obstet Gynecol. 2000; 15 (Available from:): 292-296
- Comparison of cervical lengths using transabdominal and transvaginal sonography in midpregnancy.J Ultrasound Med. 2013; 32 (Available from:): 1721-1728
- Transabdominal scanning of the cervix at the 20-week morphology scan: comparison with transvaginal cervical measurements in a healthy nulliparous population.Aust N Z J Obstet Gynaecol. 2010; 50 (Available from:): 523-527
- Transabdominal evaluation of uterine cervical length during pregnancy fails to identify a substantial number of women with a short cervix.J Matern Fetal Neonatal Med. 2012; 25 (Available from:): 1682-1689
- Correlation Between Cervical Lengths Measured by Transabdominal and Transvaginal Sonography for Predicting Preterm Birth.J Ultrasound Med. 2016; 35 (Available from:): 537-544
- Not transabdominal!.Am J Obstet Gynecol. 2016; 215 (Available from:): 739-44 e1
- Transabdominal ultrasound is appropriate.Am J Obstet Gynecol. 2016; 215 (Available from:): 739-43 e1
- Influence of cut-off value on prevalence of short cervical length.Ultrasound Obstet Gynecol. 2017; 49 (Available from:): 330-336
- Cervical length at 22-24 weeks of gestation: comparison of transvaginal and transperineal-translabial ultrasonography.Ultrasound Obstet Gynecol. 2001; 17 (Available from:): 335-340
- A comparison of ultrasonic measurement techniques for the maternal cervix in the second trimester.Australas J Ultrasound Med. 2015; 18 (Available from:): 118-123
- Correlation of uterine cervical length measurement from transabdominal, transperineal and transvaginal ultrasonography.J Med Assoc Thai. 2004; 87 (Available from:): 326-332
- Transvaginal versus transperineal ultrasonography: a blinded comparison in the assessment of cervical length at midgestation.Am J Obstet Gynecol. 1998; 179 (Available from:): 852-857
- Comparison of transperineal and transvaginal sonography in predicting preterm delivery.J Clin Ultrasound. 2004; 32 (Available from:): 225-230
- Ultrasonography for cervical length measurement: agreement between transvaginal and translabial techniques.Obstet Gynecol. 2000; 96 (Available from:): 554-558
- Transperineal versus endovaginal ultrasonographic examination of the cervix in the midtrimester: a blinded comparison.Am J Obstet Gynecol. 1999; 181 (Available from:): 780-783
- Digital examination and transperineal ultrasonographic measurement of cervical length to assess risk of preterm delivery.Int J Gynaecol Obstet. 1997; 59 (Available from:): 223-228
- The accuracy of digital examination and ultrasound in the evaluation of cervical length.Obstet Gynecol. 1992; 79 (Available from:): 214-218
- Measurement of cervical length in pregnancy: comparison between vaginal ultrasonography and digital examination.Obstet Gynecol. 1990; 76 (Available from:): 172-175
- Cervical ultrasonography compared with manual examination as a predictor of preterm delivery.Am J Obstet Gynecol. 1997; 177 (Available from:): 723-730
- Ultrasonographic examination of the uterine cervix is better than cervical digital examination as a predictor of the likelihood of premature delivery in patients with preterm labor and intact membranes.Am J Obstet Gynecol. 1994; 171 (Available from:): 956-964
- A longitudinal study of the cervix in pregnancy using transvaginal ultrasound.Br J Obstet Gynaecol. 1996; 103 (Available from:): 16-18
- Transvaginal sonography of cervical width and length during pregnancy.J Ultrasound Med. 1992; 11 (Available from:): 465-467
- Cervical length in normal pregnancy as measured by transvaginal sonography.Int J Gynaecol Obstet. 1997; 58 (Available from:): 313-315
- Cervical length at 11-14 weeks' and 22-24 weeks' gestation evaluated by transvaginal sonography, and gestational age at delivery.Ultrasound Obstet Gynecol. 2003; 21 (Available from:): 135-139
- Serial translabial sonographic measurement of cervical dimensions between 24 and 34 weeks' gestation in pregnant Thai women.Ultrasound Obstet Gynecol. 2002; 20 (Available from:): 168-173
- Cervical length at 23 weeks of gestation: prediction of spontaneous preterm delivery.Ultrasound Obstet Gynecol. 1998; 12 (Available from:): 312-317
- Progressive cervical length changes versus single cervical length measurement by transvaginal ultrasound for prediction of preterm delivery.Gynecol Obstet Invest. 2007; 64 (Available from:): 175-179
- Longitudinal assessment of endocervical canal length between 15 and 24 weeks' gestation in women at risk for pregnancy loss or preterm birth.Obstet Gynecol. 1998; 92 (Available from:): 31-37
- Changes in cervical length and the risk of preterm labor.Am J Obstet Gynecol. 2002; 186 (Available from:): 887-889
- Predictive accuracy of changes intransvaginal sonographic cervical length over time for preterm birth: a systematic review and metaanalysis.Am J Obstet Gynecol. 2015; 213 (Available from:): 789-801
- Clinical significance of cervical length shortening before 31 weeks' gestation assessed by longitudinal observation using transvaginal ultrasonography.J Obstet Gynaecol Res. 2008; 34 (Available from:): 805-811
- Predictive Accuracy of Serial Transvaginal Cervical Lengths and Quantitative Vaginal Fetal Fibronectin Levels for Spontaneous Preterm Birth Among Nulliparous Women.JAMA. 2017; 317 (Available from:): 1047-1056
- Use of transvaginal ultrasonography to predict preterm birth in women with a history of preterm birth.Ultrasound Obstet Gynecol. 2008; 32 (Available from:): 640-645
- Cervical funneling: sonographic criteria predictive of preterm delivery.Ultrasound Obstet Gynecol. 1997; 10 (Available from:): 161-166
- Monitoring the effacement of the uterine cervix by transperineal sonography: a new perspective.J Ultrasound Med. 1995; 14 (Available from:): 719-724
- Spontaneously changing gravid cervix: clinical implications and prognostic features.Radiology. 1995; 196 (Available from:): 721-724
- Cervical length and funneling at 23 weeks of gestation in the prediction of spontaneous early preterm delivery.Ultrasound Obstet Gynecol. 2001; 18 (Available from:): 200-203
- Second-trimester cervical sonography: features other than cervical length to predict spontaneous preterm birth.Obstet Gynecol. 2004; 103 (Available from:): 457-462
- Does the presence of a funnel increase the risk of adverse perinatal outcome in a patient with a short cervix?.Am J Obstet Gynecol. 2005; 192 (Available from:): 1060-1066
- Prediction of preterm birth by second trimester cervical sonography in twin pregnancies.Ultrasound Obstet Gynecol. 2000; 15 (Available from:): 288-291
- Natural history of cervical funneling in women at high risk for spontaneous preterm birth.Obstet Gynecol. 2007; 109 (Available from:): 863-869
- Clinical significance of the presence of amniotic fluid ‘sludge’ in asymptomatic patients at high risk for spontaneous preterm delivery.Ultrasound Obstet Gynecol. 2007; 30 (Available from:): 706-714
- Amniotic fluid "sludge"; prevalence and clinical significance of it in asymptomatic patients at high risk for spontaneous preterm delivery.J Matern Fetal Neonatal Med. 2018; 31 (Available from:): 135-140
- Impact of amniotic fluid "sludge" on the risk of preterm delivery.J Matern Fetal Neonatal Med. 2015; 28 (Available from:): 1176-1180
- Amniotic fluid "sludge" is an independent risk factor for preterm delivery.J Matern Fetal Neonatal Med. 2016; 29 (Available from:): 120-125
- Midtrimester intra-amniotic sludge and the risk of spontaneous preterm birth.Am J Perinatol. 2011; 28 (Available from:): 815-820
- Cervical funneling or intra-amniotic debris and preterm birth among nulliparous women with a midtrimester cervical length less than 30 mm.Ultrasound Obstet Gynecol. 2017; (Available from:)
- Clinical implication of intra-amniotic sludge on ultrasound in patients with cervical cerclage.Ultrasound Obstet Gynecol. 2010; 36 (Available from:): 482-485
- Vaginal progesterone to prevent preterm birth in pregnant women with a sonographic short cervix: clinical and public health implications.Am J Obstet Gynecol. 2016; 214 (Available from:): 235-242
- Rate of sonographic cervical shortening and the risk of spontaneous preterm birth.Am J Obstet Gynecol. 2012; 206 (Available from:): 234 e1-5
- The rate of cervicalchange and the phenotype of spontaneous preterm birth.Am J Obstet Gynecol. 2011; 205 (Available from:): 130 e1-6
- Prediction of spontaneous preterm birth in asymptomatic twin pregnancies using the change in cervical length over time.Am J ObstetGynecol. 2010; 202 (Available from:): 155 e1-4
- Follow-up cervical length in asymptomatic high-risk women and the risk of spontaneous preterm birth.J Perinatol. 2011; 31 (Available from:): 318-323
- Amnion-chorion separation after 17 weeks' gestation.Obstet Gynecol. 1999; 94 (Available from:): 1024-1026
- Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial.Ultrasound Obstet Gynecol. 2011; 38 (Available from:): 18-31
- Effectiveness of progesterone, cerclage and pessary for preventing preterm birth in singleton pregnancies: a systematic review and network meta-analysis.BJOG. 2017; 124 (Available from:): 1176-1189
- Second-trimester cervical ultrasound: associations with increased risk for recurrent early spontaneous delivery.Obstet Gynecol. 2000; 95 (Available from:): 222-226
- Transvaginal ultrasonography to predict preterm birth in women with bicornuate or didelphus uterus.J Matern Fetal Neonatal Med. 2012; 25 (Available from:): 1960-1964
- Rates of recurrent preterm birth by obstetrical history and cervical length.Am J Obstet Gynecol. 2005; 193 (Available from:): 1170-1174
- Cervical cerclage for prevention of preterm delivery in women with short cervix: randomised controlled trial.Lancet. 2004; 363 (Available from:): 1849-1853
- Timing of mid-trimester cervical length shortening in high-risk women.Ultrasound Obstet Gynecol. 2009; 33 (Available from:): 70-75
- Transvaginal ultrasonography of the cervix to predict preterm birth in women with uterine anomalies.Obstet Gynecol. 2005; 106 (Available from:): 553-556
- Transvaginal ultrasonography in the prediction of preterm birth after treatment for cervical intraepithelial neoplasia.Obstet Gynecol. 2006; 107 (Available from:): 37-44
- Prior cone biopsy: prediction of preterm birth by cervical ultrasound.Am J Obstet Gynecol. 2004; 191 (Available from:): 1393-1397
- Prediction of preterm delivery with transvaginal ultrasonography of the cervix in patients with high-risk pregnancies: does cerclage prevent prematurity?.Am J Obstet Gynecol. 1999; 181 (Available from:): 809-815
- Cervical length for prediction of preterm birth in women with multiple prior induced abortions.Ultrasound Obstet Gynecol. 2008; 31 (Available from:): 198-200
- Interval from loop electrosurgical excision procedure to pregnancy and pregnancy outcomes.Obstet Gynecol. 2013; 122 (Available from:): 1154-1159
- Adverse Pregnancy Outcomes After Treatment for Cervical Intraepithelial Neoplasia.ObstetGynecol. 2016; 128 (Available from:): 1265-1273
- Progesterone effects on preterm birth in high-risk pregnancies: a randomized placebo-controlled trial.Arch Gynecol Obstet. 2011; 283 (Available from:): 423-429
- Vaginal progesterone prophylaxis for preterm birth (the OPPTIMUM study): a multicentre, randomised, double-blind trial.Lancet. 2016; 387 (Available from:): 2106-2116
- Progesterone vaginal gel for the reduction of recurrent preterm birth: primary results from a randomized, double-blind, placebo-controlled trial.Ultrasound Obstet Gynecol. 2007; 30 (Available from:): 687-696
- Interventions for women with mid-trimester short cervix: which ones work?.Ultrasound Obstet Gynecol. 2017; 49 (Available from:): 295-300
- Intra- and interobserver reproducibility of ultrasound measurements of cervical length and width in the second and third trimesters of pregnancy.Ultrasound Obstet Gynecol. 2002; 20 (Available from:): 256-262
- Ultrasound assessment of cervical length in threatened preterm labor.Ultrasound Obstet Gynecol. 2003; 21 (Available from:): 552-555
- Sonographic measurement of cervical length in threatened preterm labor in singleton pregnancies with intact membranes.Ultrasound Obstet Gynecol. 2005; 25 (Available from:): 353-356
- Sonographic cervical length in singleton pregnancies with intact membranes presenting with threatened preterm labor.Ultrasound Obstet Gynecol. 2004; 24 (Available from:): 554-557
- Cervical assessment in women with threatened preterm labor.J Matern Fetal Neonatal Med. 2005; 17 (Available from:): 309-312
- Transvaginal cervical length measurement for prediction of preterm birth in women with threatened preterm labor: a meta-analysis.Ultrasound Obstet Gynecol. 2010; 35 (Available from:): 54-64
- Impact of ultrasound cervical length assessment on duration of hospital stay in the clinical management of threatened preterm labor.Ultrasound Obstet Gynecol. 2004; 24 (Available from:): 756-760
- Targeted therapy for threatened preterm labor based on sonographic measurement of the cervical length: a randomized controlled trial.Ultrasound Obstet Gynecol. 2007; 29 (Available from:): 47-50
- Cervical length screening for prevention of preterm birth in singleton pregnancy with threatened preterm labor: systematic review and meta-analysis of randomized controlled trials using individual patient-level data.Ultrasound Obstet Gynecol. 2017; 49 (Available from:): 322-329
- Prior Ultrasound-Indicated Cerclage: Comparison of Cervical Length Screening or History-Indicated Cerclage in the Next Pregnancy.Obstet Gynecol. 2015; 126 (Available from:): 962-968
- Prior ultrasound-indicated cerclage: how should we manage the next pregnancy?.Eur J Obstet Gynecol Reprod Biol. 2015; 188 (Available from:): 129-132
- Early transvaginal ultrasonography versus early cerclage in women with an unclear history of incompetent cervix.Am J Obstet Gynecol. 2001; 184 (Available from:): 1097-1099
- History- or ultrasound-based cerclage placement and adverse perinatal outcomes.J Reprod Med. 2011; 56 (Available from:): 385-392
- Cervical length screening with ultrasound-indicated cerclage compared with history-indicated cerclage for prevention of preterm birth: a meta-analysis.Obstet Gynecol. 2011; 118 (Available from:): 148-155
- Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy.Cochrane Database Syst Rev. 2017; 6 (Available from:)CD008991
- The value of transvaginal ultrasonographic examination of the uterine cervix in predicting preterm delivery in patients with preterm premature rupture of membranes.Ultrasound Obstet Gynecol. 1998; 11 (Available from:): 23-29
- Sonographic measurement of cervical length in preterm prelabor amniorrhexis.Ultrasound Obstet Gynecol. 2004; 24 (Available from:): 550-553
- Cervical length measurement by translabial sonography in women with preterm premature rupture of membranes: can it be used to predict the latency period or peripartum maternal infection?.J Matern Fetal Neonatal Med. 2008; 21 (Available from:): 105-109
- Randomized trial of endovaginal ultrasound in preterm premature rupture of membranes.Obstet Gynecol. 1997; 89 (Available from:): 458-461
- Is there value for serial ultrasonographic assessment of cervical lengths after a cerclage?.Am J Obstet Gynecol. 2008; 198 (discussion e6. Available from:): 705 e1-6
- Change in cervical length after cerclage as a predictor of preterm delivery.Obstet Gynecol. 2000; 96 (Available from:): 346-350
- Ultrasound-indicated cervical cerclage: outcome depends on preoperative cervical length and presence of visible membranes at time of cerclage.Am J Obstet Gynecol. 2002; 187 (Available from:): 445-449
- Funneling to the stitch: an informative ultrasonographic finding after cervical cerclage.Ultrasound Obstet Gynecol. 2002; 20 (Available from:): 252-255
- Anterior uterocervical angle measurement improves prediction of cerclage failure.J Perinatol. 2017; 37 (Available from:): 375-379
- The significance of transvaginal ultrasonographic evaluation of the cervix in women treated with emergency cerclage.Am J Obstet Gynecol. 1996; 175 (Available from:): 471-476
- Association between sonographic cervical appearance and preterm delivery after a history-indicated cerclage.J Ultrasound Med. 2014; 33 (Available from:): 2181-2186
- Ultrasound cervical length measurement for prediction of delivery before 32 weeks in women with emergency cerclage for cervical insufficiency.Int J Gynaecol Obstet. 2010; 110 (Available from:): 245-248
- Effect of cervical cerclage on rate of cervical shortening.Ultrasound Obstet Gynecol. 2015; 46 (Available from:): 718-723
- Cervicovaginal fibronectin and cervical length at 23 weeks of gestation: relative risk of early preterm delivery.BJOG. 2000; 107 (Available from:): 1276-1281
- Two-step test: the combined use of fetal fibronectin and sonographic examination of the uterine cervix for prediction of preterm delivery in symptomatic patients.Acta Obstet Gynecol Scand. 2002; 81 (Available from:): 58-63
- The Preterm Prediction Study: recurrence risk of spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.Am J Obstet Gynecol. 1998; 178 (Available from:): 1035-1040
- The preterm prediction study: can low-risk women destined for spontaneous preterm birth be identified?.Am J Obstet Gynecol. 2001; 184 (Available from:): 652-655
- Sonographic measurement of cervical length and fetal fibronectin testing in threatened preterm labor.Ultrasound Obstet Gynecol. 2006; 27 (Available from:): 368-372
- Prediction of preterm delivery by fetal fibronectin in symptomatic and asymptomatic women with cervical length </=20 mm.J Matern Fetal Neonatal Med. 2017; 30 (Available from:): 294-297
- Evaluation of the ability of cervical length and fetal fibronectin measurement to predict preterm delivery in asymptomatic women with risk factors.J Matern Fetal Neonatal Med. 2015; 28 (Available from:): 153-157
- Quantitative fetal fibronectin to predict preterm birth in asymptomatic women at high risk.Obstet Gynecol. 2015; 125 (Available from:): 1168-1176
- Quantitative fetal fibronectin testing in combination with cervical length measurement in the prediction of spontaneous preterm delivery in symptomatic women.BJOG. 2016; 123 (Available from:): 1965-1971
- The predictive value of quantitative fibronectin testing in combination with cervical length measurement in symptomatic women.Am J Obstet Gynecol. 2016; 215 (Available from:): 793 e1-e8
- The value of fetal fibronectin in cervical and vaginal secretions and of ultrasonographic examination of the uterine cervix in predicting premature delivery for patients with preterm labor and intact membranes.Am J Obstet Gynecol. 1996; 175 (Available from:): 1146-1151
- Improving the screening accuracy for preterm labor: is the combination of fetal fibronectin and cervical length in symptomatic patients a useful predictor of preterm birth? A systematic review.Am J Obstet Gynecol. 2013; 208 (Available from:): 233 e1-6
- Does fetal fibronectin use in the diagnosis of preterm labor affect physician behavior and health care costs? A randomized trial.Am J Obstet Gynecol. 2004; 191 (Available from:): 235-240
- Cost-effectiveness of diagnostic testing strategies including cervical-length measurement and fibronectin testing in women with symptoms of preterm labor.Ultrasound Obstet Gynecol. 2018; 51 (Available from:): 596-603
- Fetal fibronectin testing for prevention of preterm birth in singleton pregnancies with threatened preterm labor: a systematic review and metaanalysis of randomized controlled trials.Am J Obstet Gynecol. 2016; 215 (Available from:): 431-438
- Predicting preterm birth: a cost-effectiveness analysis.Am J Obstet Gynecol. 2000; 182 (Available from:): 1589-1598
Article info
Publication history
No. 401, December 2020 (Replaces No. 257, May 2011)
Footnotes
This document reflects emerging clinical and scientific advances as of the publication date and is subject to change. The information is not meant to dictate an exclusive course of treatment or procedure. Institutions are free to amend the recommendations. The SOGC suggests, however, that they adequately document any such amendments.
Informed Consent: Everyone has the right and responsibility to make informed decisions about their care together with their health care providers. In order to facilitate this, the SOGC recommends that they provide their patients with information and support that is evidence-based, culturally appropriate, and personalized.
Language and Inclusivity: This document uses gendered language in order to facilitate plain language writing but is meant to be inclusive of all individuals, including those who do not identify as a woman/female. The SOGC recognizes and respects the rights of all people for whom the information in this document may apply, including but not limited to transgender, non-binary, and intersex people. The SOGC encourages health care providers to engage in respectful conversation with their patients about their gender identity and preferred gender pronouns and to apply these guidelines in a way that is sensitive to each person's needs.
Copyright: The contents of this document cannot be reproduced in any form, in whole or in part, without prior written permission of the publisher of the Journal of Obstetrics and Gynaecology Canada.
Identification
Copyright
© 2020 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc.
