- 1The adverse outcomes associated with diabetes in pregnancy are substantially associated with hyperglycemia as well as the co-existing metabolic environment. Women with pre-existing diabetes should receive preconception care to optimize blood sugar control and other co-morbidities. Outcomes for the fetus/neonate and the mother in both pre-gestational diabetes mellitus and gestational diabetes mellitus pregnancies are improved by multidisciplinary management whose goal is achieving optimal blood sugar control and appropriate fetal surveillance (II-2).
- 2Retrospective studies indicate that women with pre-gestational diabetes mellitus have an increased risk of stillbirth before 40 weeks of gestation when compared with the general obstetrical population. Similarly, large recent cohort and simulation studies of women with gestational diabetes mellitus pregnancies also indicate a higher risk of stillbirth between 36-39 weeks gestation (II-2).
- 3Women with gestational diabetes mellitus have a higher risk of pre-eclampsia, shoulder dystocia, Caesarean section and large for gestational age infants (II-2).
- 4Treatment of women with gestational diabetes mellitus and optimization of glycemic control reduces the risk of pre-eclampsia, shoulder dystocia, and large for gestational age infants (I).
- 5The occurrence of gestational diabetes mellitus increases the risk of developing type 2 diabetes in the future for the mother (II-2).
- 1The “preferred screening and diagnostic 2-step” approach for gestational diabetes mellitus from Diabetes Canada's 2018 guidelines is endorsed. All pregnant women should be offered screening between 24-28 weeks using a standardized non-fasting 50-g glucose challenge screening test (GCT) with plasma glucose (PG) measured 1 hour later (III-B).
- 1.1If the value is <7.8 mmol/L, no further testing is required.
- 1.2If the value of the GCT is 7.8–11.0, a 2-hour 75-g oral glucose tolerance test with fasting PG (FPG), 1-hour PG, 2-hour PG should be performed.Gestational diabetes mellitus is diagnosed if 1 value is met or exceeded:
- iFPG ≥5.3 mmol/L
- ii1-h PG ≥10.6 mmol/L
- iii2-h PG ≥9.0 mmol/L
- 1.3If the value of the GCT is ≥11.1 mmol/L, gestational diabetes mellitus is diagnosed
- 2The “alternative 1-step diagnostic” approach from Diabetes Canada's 2018 guidelines is acceptable. In this strategy pregnant women should be offered testing between 24-28 weeks using a standardized 2-hour 75-g oral glucose tolerance test with fasting plasma glucose (FPG), 1-hour plasma glucose (PG), 2-hour PG (III-B).Gestational diabetes mellitus is diagnosed if 1 value is met or exceeded:
It is recognized that the use of different diagnostic thresholds for the “preferred” and “alternate” strategies could cause confusion in certain settings. Despite this the committee has identified the importance of remaining aligned with the current Diabetes Canada guidelines as being a priority. It is thus recommended that each care centre strategically align with one of the two strategies and implement protocols to ensure consistent and uniform reporting of test results.
- iFPG ≥5.1 mmol/L
- ii1-h PG ≥10.0 mmol/L
- iii2-h PG ≥8.5 mmol/L
- 3If there is a high risk of gestational diabetes mellitus based on multiple risk factors, screening or testing should be offered during the first half of the pregnancy and repeated at 24-28 weeks gestation if initially normal. If for any reason it was missed or if there is a clinical suspicion of later onset gestational diabetes, a screening or diagnostic test should be performed (II-2B).
- 4Women with pre-existing or gestational diabetes mellitus should be provided with care by a multidisciplinary team aimed at attaining and then maintaining euglycemia (II-2B).
- 5For patients with pre-gestational diabetes mellitus or gestational diabetes mellitus, starting at 28 weeks as a baseline, with subsequent serial assessment of fetal growth every 3-4 weeks is suggested to assess the effect of maternal glycemic control on fetal growth rate and amniotic fluid volume (II-2B).
- 6Initiation of weekly assessment of fetal well-being at 36 weeks is recommended in pre-gestational diabetes mellitus and in gestational diabetes mellitus. It is also reasonable to consider weekly fetal assessment for women with diet controlled gestational diabetes mellitus beginning at 36 weeks. Acceptable methods of assessment of fetal well-being near term can include the non-stress test, non-stress test + amniotic fluid index, biophysical profile or a combination of the above (III-A).
- 7If co-morbid factors are present such as obesity, evidence of suboptimal glycemic control, large for gestational age (>90%), previous stillbirth, hypertension or small for gestational age (<10%) are present, earlier onset and/or more frequent fetal health surveillance is recommended. In specific cases where fetal growth restriction is suspected, the addition of umbilical artery and fetal middle cerebral artery Doppler assessment may be helpful (II-2A).
- 8Pregnant women with gestational diabetes mellitus or with pre-gestational diabetes mellitus should be offered induction between 38-40 weeks of gestation depending on their glycemic control and other co-morbidity factors (II2-B).
- 9Antenatal corticosteroid therapy should be administered to women with insulin-treated gestational diabetes mellitus and pregestational diabetic women at the same dosage, according to the same indications, and in the same gestational age range as that recommended for non-diabetic women (Skoll A, et al. No. 364-Antenatal Corticosteroid Therapy for Improving Neonatal Outcomes. J Obstet Gynaecol Can 2018;40:1219-39). When administered to women with preexisting or poorly controlled diabetes, close maternal glycemic surveillance is recommended (III-B). Following the first dose of betamethasone, the following insulin adjustments are recommended as per Diabetes Canada guidelines (Diabetes Canada Clinical Practice Guidelines Expert C, et al. Diabetes and Pregnancy. Can J Diabetes 2018;42 Suppl 1:S255-S82):
- •Day 1: Increase the night insulin dose by 25%
- •Days 2 and 3: Increase all insulin doses by 40%
- •Day 4: Increase all insulin doses by 20%
- •Day 5: Increase all insulin doses by 10% to 20%
- •Days 6 and 7: Gradually taper insulin doses to pre-betamethasone doses
- 10If not previously done, in women with threatened preterm labour requiring betamethasone, a screening and diagnostic test for gestational diabetes mellitus should be performed either before or at least 7 days after the administration of betamethasone (III-B).
- 11Women with GDM should be offered testing with a 75-g oral glucose tolerance test between 6 weeks and 6 months postpartum to detect prediabetes and diabetes (Diabetes Canada Clinical Practice Guidelines Expert C, et al. Diabetes and Pregnancy. Can J Diabetes 2018;42 Suppl 1:S255-S82) (II-2A).
- iFasting plasma glucose (FPG) <6.1 mmol/L
- ii2h <7.8 mmol/L
- iiiHbA1C <6.0%
- iFPG 6.1-6.9 mmol/L or
- ii2h plasma glucose (PG) 7.8-11.0 mmol/L or
- iiiHbA1C 6.0-6.4%
11.3 Type 2 Diabetes mellitus
- iFPG ≥ 7.0 mmol/L
- iiRandom PG or 2h PG ≥11.1 mmol/L
- iiiHbA1C ≥6.5%
- 12Breastfeeding is strongly recommended after delivery for all women with pre-gestational diabetes mellitus or gestational diabetes mellitus (II-2A).
Abbreviations:ACOG (American College of Obstetricians and Gynecologists), FPG (fasting plasma glucose), GCT (glucose challenge screening test), GDM (gestational diabetes mellitus), HAPO (Hyperglycemia and Adverse Pregnancy Outcome study), IADPSG (International Association of Diabetes and Pregnancy Study Groups), NND (number needed to deliver), OGTT (oral glucose tolerance test), PG (plasma glucose), PGDM (pre-gestational diabetes mellitus), RCT (randomized controlled trial), RPG (random plasma glucose), SMBG (self-monitored blood glucose)
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This document reflects emerging clinical and scientific advances on the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. Local institutions can dictate amendments to these opinions. They should be well documented if modified at the local level. None of these contents may be reproduced in any form without prior written permission of the publisher.
All people have the right and responsibility to make informed decisions about their care in partnership with their health care providers. In order to facilitate informed choice, patients should be provided with information and support that is evidence-based, culturally appropriate and tailored to their needs.
This guideline was written using language that places women at the centre of care. That said, the SOGC is committed to respecting the rights of all people—including transgender, gender non-binary, and intersex people—for whom the guideline may apply. We encourage healthcare providers to engage in respectful conversation with patients regarding their gender identity as a critical part of providing safe and appropriate care. The values, beliefs and individual needs of each patient and their family should be sought and the final decision about the care and treatment options chosen by the patient should be respected.
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- Corrigendum to “Guideline No. 393-Diabetes in Pregnancy” [Journal of Obstetrics and Gynaecology Canada 41/12 (2019) 1814–1825]Journal of Obstetrics and Gynaecology Canada Vol. 42Issue 10