A comparison of no medication versus methyldopa or labetalol in chronic hypertension during pregnancy.

Three hundred women with mild chronic hypertension at 6 to 13 weeks' gestation were randomly allocated to receive either methyldopa or labetalol or be in the control group. Thirty-seven women (12%) were excluded for various reasons. Of the remaining 263 patients, 90 received no drug, 87 received methyldopa, and 86 received labetalol. All 263 were followed throughout pregnancy with serial renal function tests and serial assessment of fetal status. There were no differences among the three groups in mean systolic or diastolic blood pressures, mean gestational age, or initial laboratory findings at time of entry. Patients treated with medications had significantly lower (p less than 0.0001) systolic and diastolic blood pressures throughout gestation compared with the no-medication group. Among the control group there was a spontaneously significant lowering (p less than 0.0001) of both systolic and diastolic blood pressures at 14 to 26 weeks' gestation. However, there were no differences among the three groups regarding the incidences of either superimposed preeclampsia (15.6%, 18.4%, and 16.3%, respectively), abruptio placentae (2.2%, 1.1%, and 2.3%, respectively), or preterm delivery (10%, 12.5%, and 11.6%, respectively). In addition, there were no differences among the groups regarding gestational age at delivery, birth weight, incidence of fetal growth retardation, or neonatal head circumference. There was one midtrimester loss in the methyldopa group and one stillbirth in each of the other groups. We conclude that treatment of maternal blood pressure in mild chronic hypertension during pregnancy did not improve perinatal outcome.