This study was undertaken to identify risk factors associated with adverse maternal outcome in pregnancies complicated by eclampsia. This was a descriptive study of 399 consecutive women with eclampsia whose cases were managed at one perinatal center between August 1977 and July 1998. Data were collected. Risk factors studied included maternal age, race, parity, preexisting medical complications, and clinical and laboratory findings. Outcome variables were maternal morbidities. Data were analyzed by either chi(2) analysis or the unpaired Student t test as appropriate. In the entire cohort of women with eclampsia major maternal complications included abruptio placentae (10%), HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome (11%), disseminated intravascular coagulopathy (6%), neurologic deficits and aspiration pneumonia (7%), pulmonary edema (5%), cardiopulmonary arrest (4%), acute renal failure (4%), and death (1%, n = 2 patients with antepartum onset). Women with antepartum eclampsia had significantly higher incidences of abruptio placentae (12% vs 6%; P <.05) and HELLP syndrome (14% vs 4%; P =. 005) than did those in whom eclampsia developed post partum. In contrast, women with postpartum eclampsia were more likely to have neurologic deficits develop (9% vs 2%; P =.0006) than were those with antepartum eclampsia. In addition, women in whom eclampsia developed at