Maternal Gestational Diabetes Increases Risk for Adverse Perinatal Outcomes

Mothers with gestational diabetes mellitus (GDM) had a higher risk of preterm birth, preeclampsia, macrosomia, cesarean delivery, and other perinatal outcomes compared with mothers without diabetes, according to recent research published in Diabetologia.

Cécile Billionnet, MSc, PhD, from the Department of Public Health Studies, Division of Statistics, Strategic Research and Development, National Health Insurance, in Paris, France, and colleagues analyzed 796,346 deliveries in France during 2012 after 22 weeks’ gestation, with 57,629 deliveries (7.24%) from mothers with GDM.

Data from deliveries were obtained from a national health insurance system and hospital discharge database, while GDM diagnosis was determined by diagnosis at hospital and through use of glucose-lowering agents. The researchers performed analysis on deliveries >28 weeks’ gestation to avoid immortal time bias, as well as analysis of adverse outcomes in deliveries >37 weeks’ gestation.

After analyzing deliveries occurring after 28 weeks, the researchers found a greater risk of macrosomia (odds ratio [OR] = 1.8; 95% CI, 1.7-1.8), preeclampsia and eclampsia (OR = 1.7; 95% CI, 1.6-1.7), cesarean section (OR = 1.4; 95% CI, 1.4-1.4), preterm birth (OR = 1.3; 95% CI, 1.3-1.4), birth trauma (OR = 1.3; 95% CI, 1.1-1.5), cardiac malformations (OR = 1.3; 95% CI, 1.1 -1.4), and respiratory distress (OR = 1.1; 95% CI, 1.0-1.3) in mothers with GDM compared with mothers without GDM.

There was also a higher risk of adverse perinatal outcomes seen in mothers who used insulin to treat their GDM compared with mothers who controlled their GDM through diet.

For deliveries >37 weeks’ gestation, the researchers found a 30% increased risk of perinatal mortality for mothers with GDM compared with mothers who did not have diabetes, regardless of how GDM was treated compared.  There was no difference in risk for the other outcomes for deliveries >28 weeks’ gestation.

The investigators performed another analysis to eliminate undiagnosed pre-gestational diabetes from their results by excluding 1376 women (6.8% insulin-treated, 0.7% diet-treated) who delivered after 28 weeks and 1171 women (7.3% insulin-treated, 0.64% diet-treated) who delivered after 37 weeks for whom insulin or oral glucose-lowering tablets were administered within one year following delivery. 

There was no significant risk of perinatal mortality for deliveries after 37 weeks in the insulin-treated group; however, a moderate increase in perinatal mortality was seen in the diet-treated group (OR = 1.3; 95% CI, 1.0-1.6).

“We have clearly demonstrated that GDM is a disease related to adverse pregnancy outcomes and that most of the risks are higher in women with insulin-treated GDM,” Dr Billionnet and colleagues wrote in their study.

“By restricting analysis to deliveries after 37 weeks and excluding cases of undiagnosed pre-gestational diabetes, we identified a moderate increase in perinatal mortality in non-insulin-treated women with GDM. Although more investigation is needed, this study helps illuminate the controversy about timing of delivery in GDM pregnancy.”

Reference

Billionnet C, Mitanchez D, Weill A, et al. Gestational diabetes and adverse perinatal outcomes from 716,152 births in France in 2012 [published online February 15, 2017). Diabetologia. doi: 10.1007/s00125-017-4206-6