Hydralazine for treatment of severe hypertension in pregnancy: meta-analysis.
OBJECTIVE
To review outcomes in randomised controlled trials comparing hydralazine against other antihypertensives for severe hypertension in pregnancy.


METHODS
Meta-analysis of randomised controlled trials (published between 1966 and September 2002) of short acting antihypertensives for severe hypertension in pregnancy. Independent data abstraction by two reviewers. Data were entered into RevMan software for analysis (fixed effects model, relative risk and 95% confidence interval); in a secondary analysis, risk difference was also calculated.


RESULTS
Of 21 trials (893 women), eight compared hydralazine with nifedipine and five with labetalol. Hydralazine was associated with a trend towards less persistent severe hypertension than labetalol (relative risk 0.29 (95% confidence interval 0.08 to 1.04); two trials), but more severe hypertension than nifedipine or isradipine (1.41 (0.95 to 2.09); four trials); there was significant heterogeneity in outcome between trials and differences in methodological quality. Hydralazine was associated with more maternal hypotension (3.29 (1.50 to 7.23); 13 trials); more caesarean sections (1.30 (1.08 to 1.59); 14 trials); more placental abruption (4.17 (1.19 to 14.28); five trials); more maternal oliguria (4.00 (1.22 to 12.50); three trials); more adverse effects on fetal heart rate (2.04 (1.32 to 3.16); 12 trials); and more low Apgar scores at one minute (2.70 (1.27 to 5.88); three trials). For all but Apgar scores, analysis by risk difference showed heterogeneity between trials. Hydralazine was associated with more maternal side effects (1.50 (1.16 to 1.94); 12 trials) and with less neonatal bradycardia than labetalol (risk difference -0.24 (-0.42 to -0.06); three trials).


CONCLUSIONS
The results are not robust enough to guide clinical practice, but they do not support use of hydralazine as first line for treatment of severe hypertension in pregnancy. Adequately powered clinical trials are needed, with a comparison of labetalol and nifedipine showing the most promise.
University of British Columbia, BC Women's Hospital and Health Centre, 4500 Oak Street, Vancouver, BC, Canada V6H 3N1. LMagee@cw.bc.ca
Laura A
LA
Magee
Chris
C
Cham
Elizabeth J
EJ
Waterman
Arne
A
Ohlsson
Peter
P
von Dadelszen
D000959:Antihypertensive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000139:chemically induced; D005260:Female; D006340:Heart Rate, Fetal / Q000187:drug effects; D006801:Humans; D006830:Hydralazine / Q000009:adverse effects / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D007231:Infant, Newborn; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy* / Q000503:physiopathology; D011256:Pregnancy Outcome; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors
D000959:Antihypertensive Agents; D006830:Hydralazine