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 randomized comparison of early with conservative use of antihypertensive drugs in the management of pregnancy-induced hypertension.
Two treatment strategies were compared in 155 women with pregnancy-induced hypertension who were also given comprehensive non-pharmacological care. The mean gestation at entry was 28 weeks. As long as the diastolic blood pressure (DBP) remained below 106 mmHg, oxprenolol, or oxprenolol plus dihydralazine, were given to the early treatment group, and matching placebos to the control group. Open antihypertensive treatment was provided for patients whose DBP rose above 105 mmHg. Proteinuria occurred in seven women in each group. In the early treatment group, 13 of the 78 women were delivered by caesarean section; the corresponding numbers in the control group were 27 of 76 (17 vs 36%, 95% confidence interval (CI) of difference: 5-33%); the sections included seven and 16 in the early treatment and control groups, respectively, for severe hypertension and/or fetal distress. There were five perinatal deaths, two in the early treatment group and three in the control group. Early treatment did not influence gestational age at birth or birthweight. Respiratory distress syndrome occurred in four infants in the early treated group and in 10 in the control group; 14 infants in the former group and 26 in the latter were in hospital for more than 10 days (18 vs 35%; 95% CI of difference 4-32%). These results indicate that early antihypertensive treatment with oxprenolol is safe for the fetus and newborn in pregnancy-induced hypertension, but has no advantage over non-pharmacological care in terms of fetal growth. However, it may prevent acute hypertension in late pregnancy and associated fetal distress, and thus reduce the number of caesarean sections.