Preeclampsia and Eclampsia: A Complex Interplay Between Prepregnancy Obesity, Race, and Ethnicity

Preeclampsia and eclampsia (PE/E) are major contributors to maternal morbidity and mortality in the United States, disproportionately affecting Black, Hispanic, and American Indian/Alaska Native individuals. Prepregnancy obesity is a well-established risk factor, but the variation of its association with PE/E by race and ethnicity, particularly among Asian/Pacific Islander (PI) and Hispanic subpopulations, remains unclear.

This population-based cohort study included 311 497 pregnancies at Kaiser Permanente Northern California from 2011 to 2020. We used Poisson regression to estimate adjusted relative risks (aRRs) for PE/E by prepregnancy body mass index (BMI), stratified by race and ethnicity and adjusted for sociodemographic, clinical, and neighborhood-level factors.

The overall PE/E prevalence was 4.6%, highest among Black (6.8%) and lowest among Asian/PI (4.2%) and White (4.1%) individuals. PE/E prevalence increased with higher BMI across all groups, but the strength of the association varied. Black individuals experienced the smallest BMI-associated risk increase (aRR for obesity class II-III versus healthy weight, 1.53 [95% CI, 1.28-1.82]), whereas Asian/PI (2.92 [95% CI, 2.59-3.28]) and White (2.81 [95% CI, 2.58-3.07]) individuals had the largest increases. Among Asian/PI subgroups, Filipina individuals had the highest PE/E prevalence (6.2%), and Vietnamese individuals had the largest BMI-related risk increase (aRR, 3.83 [95% CI, 2.20-6.68]). Among Hispanic subgroups, Mexican individuals had the highest prevalence (5.3%) and the largest BMI-related risk increase (2.41 [95% CI, 2.17-2.68]).

Prepregnancy obesity is more strongly associated with PE/E risk among Asian/PI and White individuals than Black individuals, suggesting differing underlying mechanisms. These findings can inform refined risk stratification and call for further research into the biological and structural drivers of racial and ethnic disparities in PE/E.