Gestational Diabetes and Overweight/Obesity: Analysis of Nulliparous Women in the U.S., 2011–2019

Introduction: The rates of gestational diabetes mellitus are increasing in parallel with the rates of overweight and obesity. This analysis examines nationwide trends in the population-attributable fraction for gestational diabetes mellitus associated with prepregnancy overweight and obesity. Methods: A serial, cross-sectional study was performed using U.S. population-based birth data files maintained by the National Center for Health Statistics between 2011 and 2019. Live singleton births to nulliparous women aged 15–44 years were included, and all analyses were stratified by race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, non-Hispanic Asian). Prevalences of prepregnancy overweight (25.0–29.9 kg/m² and 23.0–27.4 kg/m²) and obesity (≥30.0 kg/m² and ≥27.5 kg/m²) based on standard and Asian-specific BMI categories, respectively, were quantified. Logistic regression estimated the adjusted associations between prepregnancy overweight and obesity and gestational diabetes mellitus, with normal weight (18.0–24.9 kg/m²and 18.0–22.9 kg/m²) as the ref. Annual population-attributable fractions for gestational diabetes mellitus associated with prepregnancy overweight and obesity were calculated, which account for both the prevalence of the risk factor and the associated risk of gestational diabetes mellitus. Results: Among 11,950,881 included women, the mean maternal age was 26.3 years. From 2011 to 2019, the population-attributable fractions for gestational diabetes mellitus associated with overweight were stable (Hispanic: 12.0%–11.3%, non-Hispanic Asian: 12.1%–11.6%, p≥0.20) or decreased (non-Hispanic White: 10.8%–9.4%, non-Hispanic Black: 12.3%–9.2%, p<0.002); the population-attributable fractions for gestational diabetes mellitus associated with obesity were stable (non-Hispanic Black: 36.3%–37.9%, p=0.11) or increased (non-Hispanic White: 30.9%–33.3%, Hispanic: 27.2%–33.3%, non-Hispanic Asian 12.2%–15.4%, p<0.001). Conclusions: The population-attributable fractions for gestational diabetes mellitus associated with obesity largely increased in the past decade, underscoring the importance of optimizing weight before pregnancy.