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.]
Placebo-controlled trial of atenolol in treatment of pregnancy-associated hypertension.
Atenolol was compared with placebo in a randomised and double-blind prospective study of 120 women with mild to moderate pregnancy-associated hypertension who were also initially managed conventionally by bed rest. Atenolol given once daily significantly reduced blood-pressure, prevented proteinuria, and reduced the number of hospital admissions. Loss of blood-pressure control leading to withdrawal from the study was commoner among the placebo group, whose babies had a high morbidity. Respiratory distress syndrome occurred only in the placebo group. Intrauterine growth retardation, neonatal hypoglycaemia, and hyperbilirubinaemia occurred with the same frequency in the two groups. Neonatal bradycardia was more common after atenolol but the systolic blood-pressure of the babies was the same in both groups. There was no difference between the groups in maternal symptoms which could have been attributed to beta-blocker therapy. Thus atenolol is more effective than conventional obstetric management in this form of hypertension and does not adversely affect mother or baby.