Abstract 68: The Association of Pre-Pregnancy Body Mass Index With Gestational Diabetes Across Maternal Race and Ethnicity Subgroups

Abstract

Objective: Gestational diabetes mellitus (GDM) complicates 5-11% of pregnancies within the US and maternal obesity is a strong risk factor. Asian individuals are known to have a higher risk of GDM at a lower body mass index (BMI) compared to European populations. However, Asian Americans represent a heterogenous group, and no studies have captured the variation between BMI and GDM across racial groups at a national level. Our objective was to characterize differences in the association between BMI and GDM by maternal race/ethnicity with a specific focus on Asian subgroups. Methods: We used data from the National Vital Statistics System natality files from 2016 to 2019, capturing all live births in the US, to ascertain incidence of GDM. We used logistic regression with BMI modeled as a cubic b-spline to model the association with risk (predicted probability) of GDM. All analyses were stratified by maternal race/ethnic group. Results: Of the eligible 13.3M pregnancies resulting in live births, 6.5% were affected by GDM, ranging from 5.2% among non-Hispanic Black individuals to 12.3% among Asian individuals. The incidence of GDM was highest among women with obesity with rates of 20.3% in Asian individuals, and 16.0% in American Indian and Alaska Native individuals with obesity (Figure 1A). At a BMI of 23 kg/m2 the predicted probability of GDM was 6.5% for Asian individuals compared to 2.3% for non-Hispanic Black individuals (Figure 1B). There was substantial heterogeneity across Asian ancestry subgroups between pre-pregnancy obesity and GDM incidence (Figure 1C), with Vietnamese and Korean individuals having the largest increase in risk with higher pre-pregnancy BMI (Figure 1D). Conclusion: The risk of GDM increased with higher pre-pregnancy BMI across all maternal race/ethnicity groups, but risk was higher for Asian Americans at a lower BMI. There was substantial variation in BMI-related risk of GDM across Asian ancestry subgroups, suggesting need for more tailored screening and intervention strategies for GDM.