The association between gestational diabetes and stillbirth: a systematic review and meta-analysis.

AIMS/HYPOTHESIS: Controversy exists over whether gestational diabetes increases the risk of stillbirth. The aim of this review was to examine the association between gestational diabetes and stillbirth. METHODS: We performed searches of the published literature to May 2021. Study selection and data extraction were performed in duplicate by independent reviewers. Meta-analyses of summary measures were conducted using random-effect models for cohort and case-control studies separately. The study protocol was registered in PROSPERO (registration ID CRD42020166939). RESULTS: From 9981 citations, 419 were identified for full-text review and 73 met inclusion criteria (n = 70,292,090). There was no significant association between gestational diabetes and stillbirth in cohort studies (pooled OR 1.04 [95% CI 0.90, 1.21]; I2 86.1%) or in case-control studies (pooled OR 1.57 [95% CI 0.83, 2.98]; I2 94.8%). Gestational diabetes was associated with lower odds of stillbirth among cohort studies presenting with an adjusted OR (pooled OR 0.78 [95% CI 0.68, 0.88]; I2 42.7%). Stratified analyses by stillbirth ≥28 weeks' gestation, studies published prior to 2013 and studies identified as low quality demonstrated a significantly higher odds of stillbirth in meta-regression (p = 0.016, 0.023 and 0.005, respectively). Egger's test for all included cohort studies (p = 0.018) suggests publication bias for the main meta-analysis. CONCLUSIONS/INTERPRETATION: Given the substantial heterogeneity across studies, there are insufficient data to define the relationship between stillbirth and gestational diabetes adequately. In the main analyes, gestational diabetes was not associated with an increased risk of stillbirth. However, heterogeneity across studies means this finding should be interpreted cautiously.

Pre-pregnancy Body Mass Index (BMI) and delivery outcomes in a Canadian population.

BACKGROUND: Worldwide there has been a dramatic increase in the prevalence of overweight and obesity in women of childbearing age. Growing evidence suggests that maternal overweight and obesity is associated with poor maternal and perinatal outcomes. This study evaluated the impact of maternal pre-pregnancy overweight and obesity on pregnancy, labour and delivery outcomes in a cohort of women with term, singleton pregnancies cared for by family physicians in community based practices. METHODS: This study is a secondary analysis of the All Our Babies Cohort, a prospective, community-based pregnancy cohort in Calgary, Alberta. Maternal self-reported data on height and pre-pregnancy weight from term, singleton, cephalic pregnancies (n = 1996) were linked to clinical data on pregnancy and birth events retrieved from electronic health records. Descriptive and bivariate regression analysis were used to compare pregnancy and birth outcomes between women categorized as normal weight, overweight and obese based on the pre-pregnancy BMI. Multinomial regression analysis stratified by type of labour onset examined the association between pre-pregnancy BMI and mode of delivery controlling for maternal age, pre-existent health conditions, parity, fertility treatments, history of C-section and pregnancy complications. RESULTS: The cohort consisted of 65.8% normal weight, 23.6% overweight and 10.6% obese women. Women with increased pre-pregnancy BMI were more likely to develop pregnancy complications such as preeclampsia (OR 3.5, CI 2.0-4.6 for overweight; OR 5.3, CI 3.3-8.5 for obese) and gestational diabetes (OR 3.0, CI 1.8-5.0 for overweight; OR 6.5, CI 3.7-11.2 for obese) than normal weight women. Spontaneous onset of labour was recorded in 71.2% of women with normal pre-pregnancy BMI, whereas 39.3% of overweight and 49% of obese women had their labour induced. For women with spontaneous labour, pre-pregnancy BMI was not a significant risk factor for mode of delivery, controlling for covariates. Among women with induced labor, obesity was a significant risk factor for delivery by C-section (adjusted OR 2.2; CI 1.2-4.1). CONCLUSIONS: Even among women with term, singleton pregnancies obtaining prenatal care in community-based settings, obese women who undergo labour induction are at increased risk of obstetrical interventions at delivery. These findings highlight the importance of tailored maternal care in pregnancy and at delivery of pregnant women with increased BMI in order to improve the outcomes and wellbeing of these women and their children.