Optimal gestational weight change associated with improved perinatal outcomes in women with gestational diabetes mellitus: a population-based study in the United States.

Background: Optimal gestational weight change (GWC) is little known among pregnant women with gestational diabetes mellitus (GDM).

Objectives: This study aimed to explore the optimal GWC ranges for women with GDM and validate these ranges compared with the Institute of Medicine (IOM) guidelines.

Methods: A population-based cohort study using natality data from the National Center for Health Statistics in the United States included 1,338,460 mother-infant pairs with GDM from 2014 to 2020. Poisson regression models were performed to identify GWC ranges (GDM targets) associated with acceptable risks (<10% increase) for a severity-weighted composite outcome including preterm birth (PTB) <37 wk, large for gestational age (LGA, birthweight >90th percentile) and small for gestational age (SGA, birthweight <10th percentile). These targets were validated in individual outcomes including PTB, LGA, SGA, hypertensive disorders of pregnancy, neonatal intensive care unit admission, and neonatal respiratory morbidity, and compared with the IOM guidelines using logistic regression models with population-attributable fractions (PAFs) calculated.

Results: The severity-weighted composite outcome had a U-shaped or a J-shaped relationship with GWC across body mass index categories. The GDM targets were 14.1 to 20.3 kg, 9.0 to 17.0 kg, 4.8 to 13.8 kg, -0.8 to 10.8 kg, -2.4 to 8.2 kg, and -8.3 to 6.0 kg for underweight, normal weight, overweight, class 1 obesity, class 2 obesity, and class 3 obesity, respectively. GWC outside the GDM or the IOM targets was associated with increased adverse perinatal outcomes in validation analyses. PAFs indicated that the IOM guidelines reduced a similar or higher proportion of adverse perinatal outcomes compared with the GDM targets for women with GDM, except for those with class 2 and 3 obesity.

Conclusions: The IOM guidelines are generally applicable for women with GDM, except for women with moderate and severe obesity. The optimal GWC ranges for women with GDM and moderate to severe obesity may be lower than the IOM guidelines.