Joint Effect of Body Mass Index and Obstructive Sleep Apnea on Preeclampsia Risk

Preeclampsia remains one of the leading causes of perinatal mortality worldwide. Little is known about the modifiable risk factors that can be identified and addressed early in pregnancy to reduce the risk of preeclampsia and its associated adverse outcomes. We sought to determine if there is a synergistic effect of prepregnancy body-mass index and obstructive sleep apnea (OSA) on the risk of preeclampsia.We conducted a retrospective cohort study of singleton pregnancies delivered in Kaiser Permanente Southern California hospitals between January 1, 2010, and December 31, 2020 (<i>n</i> = 342,349). Preeclampsia and sleep apnea were ascertained using clinical diagnosis codes. Body mass index (BMI) in kg/m² measured during prenatal care visits was categorized as normal (18.5-24.9), overweight (25-29.9), and obese (≥30). Multivariable logistic regression was used to estimate adjusted relative risks (aRR) and 95% confidence intervals (CI).Compared with normal weight in pregnancy, overweight (aRR : 1.6; 95% CI: 1.5, 1.7) and obese BMI (aRR: 2.5; 95% CI: 2.4, 2.6) were associated with an increased risk of preeclampsia. Independent of prepregnancy body-mass index, a pregnancy with OSA was associated with an increased risk of preeclampsia (aRR: 2.2; 95% CI: 1.8, 2.6). Compared with normal weight without the diagnosis of OSA in a pregnancy, overweight (aRR: 4.6; 95% CI: 2.9, 7.4) and obese BMI (aRR: 3.8; 95% CI: 3.2, 4.6) with the diagnosis of OSA were associated with an increased risk of preeclampsia.OSA and elevated body-mass index have an independent and additive relationship with preeclampsia. Overweight women at risk of preeclampsia should be advised of a higher likelihood of developing preeclampsia when both conditions occur together and may benefit from close monitoring and early interventions for these modifiable risk factors. · There is a dose-dependent association between BMI and the risk of preeclampsia.. · Coexistent obesity and OSA resulted in a stronger risk for preeclampsia.. · The combined effect of obesity and OSA on preeclampsia risk is additive rather than synergistic..