A retrospective cohort study of race/ethnicity, pre-pregnancy weight, and pregnancy complications

Abstract

Objective

To examine the relationship between race/ethnicity, pre-pregnancy overweight/obesity status, and pregnancy complications.

Methods

We conducted a retrospective cohort study among mothers with singleton live births using data from hospitals contributing to the Obstetrical Care Outcomes Assessment Program database (N = 72,697). Race was categorized as Non-Hispanic (NH) White, NH African-American, Hispanic, NH Asian, NH American Indian/Alaskan Native, and NH Native-Hawaiian/Other Pacific Islander. Pre-pregnancy overweight/obesity status was defined as body mass index (BMI)≥25 kg/m². Pregnancy complications evaluated were gestational diabetes, pre-eclampsia, and cesarean delivery. We fitted adjusted and unadjusted stratified Poisson regression models with robust standard errors. Interaction terms were used to assess statistical significance of interactions between race/ethnicity and pre-pregnancy overweight/obesity status.

Results

Most women were NH White (52.1%) and more than half had overweight/obesity (54.3%). Among women with overweight/obesity, Hispanics had a lower risk of cesarean delivery as compared to NH White (adjusted relative risk, aRR:0.89; 95%CI:0.84–0.93). Similarly, among women with overweight/obesity, Hispanic and NH Native-Hawaiian/Other Pacific Islander had a lower risk of preeclampsia (aRR:0.74; 95%CI:0.66–0.82 and aRR:0.64; 95%CI:0.44–0.92, respectively) and NH African-American had a greater risk of gestational diabetes (aRR:1.23; 95%CI:1.07–1.42) when compared with NH White women. These associations were not present among normal-weight women. Women with overweight/obesity, when compared with women of normal-weight, had an increased risk of gestational diabetes and cesarean delivery among all race/ethnicities except NH American Indian/Alaskan Native and NH Native-Hawaiian/Other Pacific Islander, respectively (p-values < .05). The multiplicative interaction terms between race/ethnicity and overweight/obesity status were significant for all three complications (interaction p-values < .05).

Conclusion

Pre-pregnancy overweight/obesity status modifies associations of race/ethnicity with pregnancy complications. Conversely, race/ethnicity modifies associations of pre-pregnancy overweight/obesity status with pregnancy complications. Our findings have implications for public health and clinical practice, supporting the focus on healthy preconception weight and risk stratification across racial/ethnic groups.

Keywords:

• Race
• pre-pregnancy weight
• pregnancy complications

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from Obstetrical Care Outcome Assessment Program (OBCOAP). Restrictions apply to the availability of these data, which were used under license for this study.