Labetalol Therapy in Pregnancy-Induced Hypertension: The Effects on Fetoplacental Circulation and Fetal Outcome

Abstract

We prospectively studied the effects of oral labetalol therapy in patients with moderate to severe pregnancy induced hypertension (PIH). The outcome variables were blood pressure control, effect on umbilical artery flow velocity waveforms (UAFVW) and fetal outcome. Forty-two patients were recruited, all had moderate to severe PIH. The mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) on entry were 154 +/- 7 mmHg and 104 +/- 5 mmHg, respectively. All had significant proteinuria. After 1 week on labetalol therapy, 85% of patients had their blood pressure controlled. The reduction in both SBP and DBP was statistically significant. There were no significant changes in UAFVW, Resistance Index (RI), uric acid or platelets. The mean fetal age on entry was 246 +/- 10 days while gestation at delivery was 258 +/- 17 days. The mean birth weight was 2712 +/- 609 g. No perinatal mortality occurred in this study. Labetalol is an effective drug in controlling blood pressure and does not adversely affect the UAFVW. No neonatal problems were attributed directly to the drug. Fetal outcome was satisfactory despite the 12 fetuses that were growth-retarded. Labetalol allows safe prolongation of pregnancies complicated by PIH.