HbA1c and Gestational Weight Gain Are Factors that Influence Neonatal Outcome in Mothers with Gestational Diabetes

Background: Maternal glucose and weight gain are related to neonatal outcome in women with gestational diabetes mellitus (GDM). The aim of this study was to explore the influence of average third-trimester HbA1c and excess gestational weight gain on GDM neonatal complications. Materials and Methods: This observational study included 2037 Spanish singleton pregnant women with GDM followed in our Diabetes and Pregnancy Unit. The maternal HbA1c level was measured monthly from GDM diagnosis to delivery. Women were compared by average HbA1c level and weight gain categorized into <= or > the current Institute of Medicine (IOM) recommendations for body mass index. The differential effects of these factors on large-for-gestational-age birth weight and a composite of neonatal complications were assessed. Results: Women with an average third-trimester HbA1c >= 5.0% (n = 1319) gave birth to 7.3% versus 3.8% (p = 0.005) of large-for-gestational-age neonates and 22.0% versus 16.0% (p = 0.006) of neonates with complications. Women with excess gestational weight gain (n = 299) delivered 12.5% versus 5.2% (p < 0.001) of large-for-gestational-age neonates and 24.7% versus 19.0% (p = 0.022) of neonates with complications. In an adjusted multiple logistic regression analysis among mothers exposed to the respective risk factors, similar to 47% and 52% of large-for-gestational-age neonates and 32% and 37% of neonatal complications were potentially preventable by attaining an average third-trimester HbA1c level < 5.0% and optimizing gestational weight gain. Conclusions: Average third-trimester HbA1c level >= 5% and gestational weight gain above the IOM recommendation are relevant risk factors for neonatal complications in mothers with gestational diabetes.