Improvement in control of maternal blood pressure with use of beta-blockers would be worthwhile only if it were reflected in substantive benefits for mother and/or baby, and none have been clearly demonstrated. The effect of beta-blockers on perinatal outcome is uncertain; the worrying trend to an increase in SGA infants is partly dependent on one small outlying trial. Large randomised trials are needed to determine whether antihypertensive therapy in general (rather than beta-blocker therapy specifically) results in greater benefit than risk, for treatment of mild-moderate pregnancy hypertension. If so, then it would be appropriate to consider which antihypertensive is best, and beta-blockers should be evaluated.
[Note: the seventeen reports in the awaiting classification section of the review may alter the conclusions of the review once assessed.]
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.