Medical and Surgical Complications in Pregnancy
Anti-hypertensive of choice in severe pregnancy induced hypertension (PIH) is (AIPG 2010)
1. Hypertension in pregnancy is a common cause of maternal and perinatal morbidity and mortality. If drug therapy is deemed necessary, the use of oral antihypertensives with established fetal safety profiles i.e., methyldopa, labetalol, hydralazine and long-acting nifedipine, are generally preferred. ACE inhibitors are contraindicated in the second and third trimesters because they are associated with a characteristic fetopathy.
2. Severe hypertension accounts for much of the maternal risk associated with hypertension in pregnancy, and more aggressive treatment is warranted. Among agents used in this clinical setting are parenteral hydralazine and labetalol. Intravenous administration of rapid-acting antihypertensive agents is generally required to achieve initial reduction of blood pressure in pregnant women with severe hypertension. Intravenous hydralazine is a drug of first choice and perhaps the most widely used agent for acute management of severe hypertension in pregnancy. Its advantages include lack of adverse effects on fetal circulation, long experience with the drug in this clinical setting, and convenient administration.
Drug Mode of action Dose
Methyl dopa Central and peripheral 250–500mg tid or qid
Labetalol Adrenoceptor antagonist 250mg tid or qid
(α and β blocker)
Nifedipine Calcium channel blocker 10–20mg bid
Hydralazine Vascular smooth muscle relaxant 10–25mg bid
3. While experience with labetalol in the acute treatment of severe hypertension in pregnancy is less well documented, comparative studies suggest that parenteral use of labetalol is at least effective and safe as hydralazine. Even so, fetal distress and neonatal bradycardia have been reported following the use of this agent.