Objective: This study was undertake to determine risk factors for adverse maternal outcomes among women with HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome. Study Design: Maternal medical records of pregnancies complicated by HELLP syndrome managed between July 1, 1992, and April 30, 1999, were reviewed. Risk factors evaluated included maternal age, parity, race, previous preeclampsia, chronic hypertension, gestational age at diagnosis, mean arterial blood pressure, nadir blood platelet count (<50,000 cells/μL vs ≥50,000 cells/μL), and peak serum levels of aspartate aminotransferase and lactate dehydrogenase. Maternal outcome variables analyzed included eclampsia, abruptio placentae, disseminated intravascular coagulopathy, pulmonary edema, pleural effusion, ascites, acute renal failure, liver hematoma, need for transfusion of blood products, cesarean delivery, and death. Statistical analysis was performed with the Student t test, the χ² test, and logistic regression analysis. Results: A total of 183 women with HELLP syndrome were studied. Eclampsia was present in 6%, abruptio placentae was present in 10%, and disseminated intravascular coagulopathy was present in 8%. Forty-one women (22%) required transfusion of blood products. Incidence of eclampsia significantly decreased with increasing gestational age, from 16% at ≤28 weeks’ gestation to 3% at >32 weeks’ gestation (P <.05) and was higher among African American patients than among white patients (12% vs 3%; P <.05). Logistic regression analysis showed an independent relationship between eclampsia and race (P <.05). Incidence of abruptio placentae was higher among women with previous preeclampsia than among women without this clinical history (26% vs 5%; P <.05). Disseminated intravascular coagulopathy was significantly associated with abruptio placentae (P <.0001) and acute renal failure (P <.0001). A nadir platelet count of <50,000/μL, a peak serum aspartate aminotransferase level of >150 U/L, and a peak serum lactate dehydrogenase level of >1400 U/L were not independent risk factors for adverse outcome. Conclusions: Among women with HELLP syndrome, African American race is a risk factor for eclampsia. Both acute renal failure and abruptio placentae are associated with disseminated intravascular coagulopathy. Laboratory parameters of HELLP syndrome are not independent risk factors for adverse maternal outcome. (Am J Obstet Gynecol 2000;183:444-8.)