We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2013) and reference lists of retrieved studies.
SELECTION CRITERIA: DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data.
MAIN RESULTS: Forty-nine trials (4723 women) were included. Twenty-nine trials compared an
antihypertensive drug with placebo/no
antihypertensive drug (3350 women). There is a halving in the risk of developing severe
hypertension associated with the use of
antihypertensive drug(s) (20 trials, 2558 women; risk ratio (RR) 0.49; 95% confidence interval (CI) 0.40 to 0.60; risk difference (RD) -0.10 (-0.13 to -0.07); number needed to treat to harm (NNTH) 10 (8 to 13)) but little evidence of a difference in the risk of
pre-eclampsia (23 trials, 2851 women; RR 0.93; 95% CI 0.80 to 1.08). Similarly, there is no clear effect on the risk of the baby dying (27 trials, 3230 women; RR 0.71; 95% CI 0.49 to 1.02),
preterm birth (15 trials, 2141 women; RR 0.96; 95% CI 0.85 to 1.10), or small-for-gestational-age babies (20 trials, 2586 women; RR 0.97; 95% CI 0.80 to 1.17). There were no clear differences in any other outcomes.Twenty-two trials (1723 women) compared one
antihypertensive drug with another. Alternative drugs seem better than
methyldopa for reducing the risk of severe
hypertension (11 trials, 638 women; RR (random-effects) 0.54; 95% CI 0.30 to 0.95; RD -0.11 (-0.20 to -0.02); NNTH 7 (5 to 69)). There is also a reduction in the overall risk of developing
proteinuria/
pre-eclampsia when beta blockers and
calcium channel blockers considered together are compared with
methyldopa (11 trials, 997 women; RR 0.73; 95% CI 0.54 to 0.99). However, the effect on both severe
hypertension and
proteinuria is not seen in the individual drugs. Other outcomes were only reported by a small proportion of studies, and there were no clear differences.
AUTHORS' CONCLUSIONS: