Nifedipine versus expectant management in mild to moderate hypertension in pregnancy

Objective - To compare the effect of routine treatment with the calcium channel blocker nifedipine in mild to moderate hypertension in pregnancy. Design - Randomised clinical trial. Setting - General and University hospitals. Participants - Pregnant women, between 12 and 34 weeks of gestation, with chronic, pregnancy-induced or unclassifiable hypertension and diastolic pressure between 90 and 110 mmHg. Methods - Eligible women were randomly assigned treatment with slow-release nifedipine, 10 mg twice daily until delivery, or no treatment. In the no treatment group nifedipine was given if the diastolic pressure exceeded 110 mmHg. A total of 145 women were assigned nifedipine and 138 no treatment. Results - In the nifedipine group 45.0% of women were delivered before term, compared with 37.0% in the no treatment group; the difference was not significant. In all, 56.3% of women allocated nifedipine and 62.1% allocated no treatment underwent caesarean section; the difference was not statistically different (OR 0.7, 95% CI 0.4-1.1). There was no significant difference between the two groups in the percentage of babies weighing less than the 10th centile (OR 0.8; 95% CI 0.4-1.4) or in the mean birthweight. The frequency of admission of infants to the neonatal intensive care unit was not affected by treatment. Conclusions - This trial found no benefit on pregnancy outcome of routine treatment with nifedipine. In clinical practice, the treatment of hypertension in pregnancy may be delayed until the hypertension becomes severe.