P reeclampsia in a first pregnancy is reportedly the strongest risk factor for having preeclampsia in subsequent pregnancies, with the odds for recurrence increasing with earlier gestational age at prior delivery. There is no information, however, on the absolute recurrence risk across the spectrum of gestational ages in prior deliveries. In this population-based study, the authors aimed to establish guides for recurrence risk based on gestational age at the first pregnancy complicated by preeclampsia and to determine whether demographic and clinical factors modify the risk.Taking data from a state-wide program in Missouri that links maternal birth and neonatal death certificates, the study population consisted of women who delivered their first two singleton births from 1989 through 1997 (n = 103,860). These were divided into two groups: those with preeclampsia (n = 6157) vs. those without (n = 97,703) during the first births. Covariates evaluated included maternal age, race, medical history, interbirth interval, change in paternity, smoking during pregnancy, body mass index (BMI), previous fetal death or stillbirth, small-for-gestational-age (SGA) newborns, and gestational age in the first delivery. The risk of preeclampsia was computed as the percentage of women in each group who developed preeclampsia during the second pregnancy. Regression models for both groups determined the adjusted risk ratios for known confounders between primary exposure and preeclampsia during the second pregnancy and adjusted for risk ratios for known confounders.In second pregnancies, 14.7% of women who had preeclampsia in the first pregnancy had a recurrence vs. recurrence in1.8% of those who did not (risk ratio, 8.4; 95% confidence interval, 7.8-9.1). Earlier gestational age at first delivery was a significant predictor of subsequent preeclampsia in both groups, although the association was markedly increased in those with prior preeclampsia and preterm birth. In women with prior preeclampsia, the risk of recurrence in those who delivered at term in the first pregnancy was approximately 12%, versus nearly 40% for those who delivered at <28 weeks' gestation. Increasing BMI also progressively increased risk in both groups at all gestational ages, while the length of the interbirth interval and paternity change had no impact.These findings suggest that the primary markers for recurrent preeclampsia in a second pregnancy are earlier gestational age in the first pregnancy and higher prepregnancy BMI (a modifiable risk). The same risk factors apply to women who did not have preeclampsia in a previous preg-nancy, although the magnitude of risk is much lower than in those who did. The authors suggest that these results could form the basis for counseling women with prior preeclampsia on the risk of recurrence in subsequent pregnancies. P arturients with preeclampsia (PE) are known to be at increased risk of hypertension, ischemic heart disease, and premature cardiovascular death, compared with normotensive women. It is not clear whether c...