What is an appropriate gestational weight gain for women with gestational diabetes mellitus: based on the adverse pregnancy outcomes of over 12 thousand participants?

Background: Evidence showed possible benefits of a less gestational weight gain (GWG) than the US Institute of Medicine (IOM) recommendation in gestational diabetes mellitus (GDM) pregnancy. Here, we aimed to explore an appropriate GWG range in GDM women according to adverse pregnancy outcomes. Methods: We enrolled all the singleton GDM pregnant women (n = 14,213) from January 2015 to December 2018 in Xi'an, Northwest China. According to the pre-pregnancy body mass index (BMI), they were classified into the Underweight (< 18.5 kg/m²), Normal weight (18.5–24.9 kg/m²⁾, Overweight (25.0–29.9 kg/m²) and Obesity (≥ 30.0 kg/m²) group, respectively. Logistic regression analysis was used to calculate the odds ratio (OR) and 95% confidence intervals (95% CI). The appropriate ranges of GWG were determined based on a significant protective association (OR < 1). Results: Totally, 12,712 participants were finally recruited. There were 1180 (9.3%), 9134 (71.9%), 2097 (16.5%), and 301 (2.4%) patients in the Underweight, Normal weight, Overweight, and Obesity groups, respectively. Adverse outcomes increased with the elevation of pre-pregnancy BMI. Among them, the risk of cesarean section was the highest, followed by large for gestational age (LGA), small for gestational age (SGA), preeclampsia, and gestational hypertension. Through the analysis of the risk of adverse outcomes in continuous GWG categories in each group, an ideal GWG range obtained in this study was as follows: 10–15.9 kg, 8–11.9 kg, 6–7.9 kg, and -5–3.9 kg for the Underweight, Normal weight, Overweight and Obesity group, respectively. Furthermore, the ranges in this study were more protective for adverse outcomes than those from IOM. Conclusions: Based on the adverse pregnancy outcomes of over 12 thousand participants, our findings showed a more stringent GWG range for GDM women than the IOM criteria recommendation.