Risks and benefits of β-receptor blockers for pregnancy hypertension: Overview of the randomized trials

Objective: Examine the benefits/risks of β-blockers for pregnancy hypertension. Study design: Meta-analysis of relevant trials identified by comprehensive literature review (1966-97). Results: Included were 30 trials for pregnancy hypertension, and four others for perinatal outcomes only. For mild chronic hypertension treated throughout pregnancy (n=2 trials), oral β-blockers (compared with no therapy) were associated with an inconsistent increase in small for gestational age (SGA) infants (OR 2.46 [1.02, 5.92]). For mild-moderate 'late-onset' pregnancy hypertension (i.e. either chronic treated only late in pregnancy, or pregnancy-induced) (n=8 trials), oral β-blockers (compared with no therapy) were associated with a decrease in severe hypertension (OR 0.27 [0.16, 0.45]), borderline decrease in development of proteinuria (OR 0.69 [0.48, 1.02]), decrease in RDS (OR 0.33 [0.13, 0.85]), but a borderline increase in SGA infants (OR 1.47 [0.96, 2.26]). β-blockers were equivalent to other agents (n=15 trials). For severe 'late-onset' pregnancy hypertension (n=5 trials), i.v. labetalol produced less maternal hypotension (OR 0.13 [0.03, 0.71]) and fewer cesareans (OR 0.23 [0.13, 0.63]) than i.v. hydralazine/diazoxide. Conclusions: It is not clear that the benefits outweigh the risks when β-blockers are used to treat mild to moderate chronic or pregnancy-induced hypertension, given the unknown overall effect on perinatal outcomes. For severe 'late-onset' pregnancy hypertension, i.v. labetalol is safer than i.v. hydralazine or diazoxide. Copyright (C) 2000 Elsevier Science Ireland Ltd.