This study was undertaken to determine retrospectively, in women with the HELLP syndrome, the perinatal effects of corticosteroid administration for promotion of fetal lung maturity. Twenty-seven of 427 women with the HELLP syndrome treated between 1980 and 1991 received a full course of steroids prior to preterm delivery. They were compared to 27 control patients with the HELLP syndrome matched for maternal age, severity of disease, gestational age, race, and sex of the fetus. Respiratory distress requiring mechanical ventilation occurred in 13 of 27 neonates who received steroid administration and in 23 of 27 who did not receive steroids (p < 0.001). The average stay in the neonatal intensive care unit was 29.8 +/- 50.6 days for the steroid-treated group and 45.2 +/- 35.3 days for the group without steroid use (p = NS). The incidence of neonatal deaths, intraventricular haemorrhage type III and IV, necrotizing enterocolitis, and retrolental fibroplasia was greater in the control group but the difference was not statistically significant.