Risk factors differ between recurrent and incident preeclampsia: a hospital-based cohort study

To examine whether risk factors, including prepregnancy body mass index (BMI), differ between recurrent and incident preeclampsia.

Data included electronic medical records of nulliparas (n = 26,613) delivering 2 times or more in Utah (2002-2010). Modified Poisson regression models were used to examine (1) adjusted relative risks (RR) of preeclampsia and 95% confidence intervals (CI) associated with prepregnancy BMI; (2) maternal risk factor differences between incident and recurrent preeclampsia among primiparous women.

In the first pregnancy, compared with normal weight women (BMI: 18.5-24.9), preeclampsia risks for overweight (BMI: 25-29.9), obese class I (BMI: 30-34.9), and obese class II/III (BMI: ≥ 35) women were 1.82 (95% CI = 1.60-2.06), 2.10 (95% CI = 1.76-2.50), and 2.84 (95% CI = 2.32-3.47), respectively, whereas second pregnancy-incident preeclampsia risks were 1.66 (95% CI = 1.27-2.16), 2.31 (95% CI = 1.67-3.20), and 4.29 (95% CI = 3.16-5.82), respectively. Recurrent preeclampsia risks associated with BMI were highest among obese class I women (RR = 1.60; 95% CI = 1.06-2.42) without increasing in a dose-response manner. Nonwhite women had higher recurrence risk than white women (RR = 1.70; 95% CI = 1.16-2.50), whereas second pregnancy-incident preeclampsia risk did not differ by race.

Prepregnancy BMI appeared to have stronger associations with risk of incident preeclampsia either in the first or second pregnancy, than with recurrence risk. Nonwhite women had higher recurrence risk.