OBJECTIVE: The objective of our study was to test the hypothesis that treatment with nifedipine for mild preeclampsia remote from term reduces the number of days of maternal hospitalization and improves pregnancy outcome. STUDY DESIGN: A total of 200 patients at 26 to 36 weeks' gestation were randomly allocated to treatment with either bed rest alone (n = 100) or bed rest in combination with nifedipine (n = 100). RESULTS: Patients receiving nifedipine had significantly lower systolic (p < 0.0001) and diastolic (p < 0.0001) blood pressures during therapy. Severe hypertension as an indication for delivery was significantly (p < 0.05) more frequent in the bed-rest-alone group. The two study groups had similar average days of maternal hospitalization (12.6 +/- 7.9 vs 12.3 +/- 10.3) and pregnancy prolongation (22.3 +/- 13.5 vs 22.5 +/- 15.7). There were no differences between groups with respect to birth weight, incidences of small-for-gestational-age infants and preterm birth, number of days spent in special care unit, or cord blood gas measurement. CONCLUSION: Nifedipine therapy for preeclampsia reduces maternal blood pressure but does not reduce number of days of maternal hospitalization or improve perinatal outcome.