To identify risk factors associated with severe preeclampsia and to determine whether these factors are similar in nulliparous and multiparous patients.Patients whose pregnancies were complicated by severe preeclampsia (n = 70) were compared retrospectively to 18,964 non-preeclamptic controls. Information on maternal demographic factors; medical, obstetric, and family histories; and neonatal outcome was retrieved and analyzed by univariate and multivariate analysis.By logistic regression, the only risk factors associated with the development of severe preeclampsia were severe obesity in all patients (adjusted odds ratio 3.5, 95% confidence interval [CI] 1.68-7.46) and a history of preeclampsia in multiparous patients (adjusted odds ratio 7.2, 95% CI 2.74-18.74).Severe obesity and a history of preeclampsia are the only maternal risk factors identified for the development of severe preeclampsia.