[HELLP syndrome. Review and update].

Whether HELLP syndrome is a distinct entity or a severe form of preeclampsia, it remains a factor of gravity. Described by Weinstein in 1982, it associates hemolysis, cytolysis (elevated liver enzymes) and thrombopenia (low platelets). The cut off for the biological parameters have to be strictly defined to avoid overdiagnosis of HELLP syndrome. The difficulty to diagnose this syndrome is real because most of the associated clinical signs are aspecific. The errors of diagnosis are more frequent when the syndrome is not associated to preeclampsia (10%), in the mid-trimester (15%) and in the postpartum (30%). The mean term of delivery is 32 weeks, the prematurity being widely induced because of the fear of maternal complications. Maternal deaths (1.1%) do not seem to be directly related to the HELLP syndrome. Subcapsular hematomas of the liver are unfrequent (0.9%). Rapid termination of pregnancy, by vaginal delivery or by cesarean, is generally recommended when the fetal lung maturity is obtained or when maternal complications appear. Conversely, conservative management is acceptable before 32 weeks. Corticosteroid therapy or hemodynamic therapy could allow to obtain fetal lung maturity. A conservative approach requires permanent materno-fetal follow-up which can only be achieved in a perinatal center integrating a neonatal intensive care unit.