Drugs for treatment of very high blood pressure during pregnancy

Abstract

Background: Very high blood pressure during pregnancy poses a serious threat to women and their babies. Antihypertensive drugs lower blood pressure. Their comparative effects on other substantive outcomes, however, is uncertain.

Objectives: To compare different antihypertensive drugs for very high blood pressure during pregnancy.

Search strategy: We searched the Cochrane Pregnancy and Childbirth Group Trials Register (28 February 2006) and CENTRAL (The Cochrane Library 2006, Issue 2).

Selection criteria: Studies were randomised trials. Participants were women with severe hypertension during pregnancy. Interventions were comparisons of one antihypertensive drug with another.

Data collection and analysis: Two review authors independently extracted data.

Main results: Twenty-four trials (2949 women) with 12 comparisons were included. Women allocated calcium channel blockers rather than hydralazine were less likely to have persistent high blood (five trials, 263 women; 6% versus 18%; relative risk (RR) 0.33, 95% confidence interval (CI) 0.15 to 0.70). Ketanserin was associated with more persistent high blood pressure than hydralazine (four trials, 200 women; 27% versus 6%; RR 4.79, 95% CI 1.95 to 11.73), but fewer side-effects (three trials, 120 women; RR 0.32, 95% CI 0.19 to 0.53) and a lower risk of HELLP (Haemolysis, Elevated Liver enzymes and Lowered Platelets) syndrome (one trial, 44 women, RR 0.20, 95% CI 0.05 to 0.81). Labetalol was associated with a higher risk of hypotension (one trial 90 women; RR 0.06, 95% CI 0.00 to 0.99) and caesarean section (RR 0.43, 95% CI 0.18 to 1.02) than diazoxide. Data were insufficient for reliable conclusions about other outcomes. The risk of persistent high blood pressure was greater for nimodipine compared to magnesium sulphate (two trials 1683 women; 47% versus 65%; RR 0.84, 95% CI 0.76 to 0.93). Nimodipine was also associated with a higher risk of eclampsia (RR 2.24, 95% CI 1.06 to 4.73) and respiratory difficulties (RR 0.28, 95% CI 0.08 to 0.99), but fewer side-effects (RR 0.68, 95% CI 0.54 to 0.86) and less postpartum haemorrhage (RR 0.41, 95% CI 0.18 to 0.92) than magnesium sulphate. Stillbirths and neonatal deaths were not reported. There are insufficient data for reliable conclusions about the comparative effects of any other drugs.

Authors' conclusions: Until better evidence is available, the choice of antihypertensive should depend on the clinician's experience and familiarity with a particular drug, and on what is known about adverse effects. Exceptions are diazoxide, ketanserin, nimodipine and magnesium sulphate, which are probably best avoided.