Type 2 diabetes and neonatal hypoglycemia: role of route of delivery and insulin infusion

Objective To compare the rate of neonatal hypoglycemia among newborns delivered by individuals with Type 2 diabetes mellitus (T2DM) in two clinical scenarios: who attempted vaginal delivery vs. had a planned cesarean delivery (CD); who had intrapartum insulin infusion vs. who did not. Methods This was a retrospective cohort study of individuals with insulin-treated T2DM who had non-anomalous singleton pregnancy and delivered at a single tertiary center (March 2012 and May 2018). Individuals with chronic renal failure, proliferative retinopathy, or major congenital anomalies were excluded. The primary outcome was neonatal hypoglycemia (blood glucose < 40 mg/dl 24 h of age). Secondary outcomes included neonatal outcomes. Multivariable Poisson regression models with robust error variance were used to examine the association between groups and the primary outcome. Adjusted relative risk (aRR) and 95% confidence intervals (CI) were calculated. Results Of 233 individuals with T2DM, 215 (92.2%) met the inclusion criteria, of whom 95 (44%) attempted vaginal delivery and 120 (56%) had a planned CD. Individuals who labored had a higher gestational age at delivery (36.6 vs. 35.8 weeks, p = .005), and higher blood glucose levels upon admission (125 vs 103, p < .001) compared to those with a planned CD. After adjustment for potential confounders, there was no difference in risk of neonatal hypoglycemia between the groups (41.2 vs 44.1%, aRR 1.05, 95% CI = 0.75-1.45). Among those who attempted vaginal delivery, 34 (35.8%) required insulin infusion. There was no difference in the risk of neonatal hypoglycemia (aRR = 0.79, 95% CI = 0.45-1.37) between newborns delivered by individuals who required insulin infusion and those who did not. Conclusion Over 40% of newborns delivered by individuals with insulin-dependent T2DM had hypoglycemia; however, there was no significant difference in the risk of hypoglycemia, irrespective of the route of delivery and the use of insulin infusion.