Comparative risk-benefit assessment of drugs used in the management of hypertension in pregnancy.

Antihypertensive treatment in pregnancy is needed to protect the mother from the dangers of severe hypertension (greater than or equal to 170/110mm Hg), particularly cerebral haemorrhage in the context of preeclampsia. There is no evidence that treatment of the hypertension confers any other benefit; the onset and progression of preeclampsia is neither prevented nor ameliorated. Therefore, there are no indications for treating mild-to-moderate hypertension (140 to 169/90 to 109mm Hg). Intravenous hydralazine and oral nifedipine are effective drugs to treat severe hypertension acutely, the latter having the advantage of ease of administration. For long term therapy, methyldopa is the only drug which has been fully assessed and shown to be safe for the neonate and infant. beta-Adrenoceptor antagonists are safe to use in the third trimester but cause significant intrauterine growth retardation when used for longer periods. ACE inhibitors are contraindicated and diuretics should be avoided. Although calcium antagonists appear to have much potential they require further assessment of their use in pregnancy.