INTRODUCTION
Hypertensive disorders are one of the most common medical disorders complicating pregnancy.1 These complicate upto 10% of pregnancies worldwide constituting one of the greatest causes of maternal and perinatal mortality and morbidity worldwide.2The American College of Obstetricians and Gynaecologists (ACOG) describes a hypertensive emergency in pregnancy as acute-onset, severe hypertension persisting for 15 min or more in setting of preeclampsia or eclampsia.3 Severe hypertension in pregnancy is defined as a systolic blood pressure (SBP) more than or equal to 160 mmHg and/or a diastolic blood pressure (DBP) more than or equal to 110 mmHg.4
A hypertensive emergency requires hospitalization, immediate antihypertensive treatment to reduce maternal blood pressure without substantially decreasing placental perfusion and compromising the fetus, and delivery of the infant as soon as possible. The goal is to achieve a target BP of less than or equal to 150/100 mmHg in order to prevent repeated, prolonged exposure to severe systolic hypertension, with subsequent loss of cerebral vasculature auto regulation. Hence antihypertensive drugs which can be used for control of hypertensive emergencies of pregnancy are nifedipine, labetalol and hydralazine.
Labetalol is a combined α- and β-adrenergic blocker that acts by causing vasodilatation. It is a pregnancy category C drug. It can be used in drowsy and unconscious patients. Its side effects includes orthostatic hypotension (due to alpha blocker action), difficulty in sleeping, drowsiness, weakness, scalp tingling, drug eruption. Labetalol is contraindicated in asthma, congestive heart failure, any degree of heart block, bradycardia, hypotension or those in cardiogenic shock.5Nifedipine is a calcium channel blocker. Nifedipine effectively dilates the arterioles in preference to veins thus producing an effective vasodilatation without producing postural hypotension. It reduces the total peripheral resistance and thereby reduces the after load. It is a pregnancy category C drug and has the advantage of being cost effective, rapid onset of action, long duration of action, oral bioavailability, easier to store and infrequent side effects.6 Sublingual route is not recommended since it produces a rapid fall of the blood pressure. However it is known to cause reflex tachycardia and headache.2 Nifedipine doesn’t adversely affect uterine or umbilical blood flow.In this study we have compared oral nifedipine and intravenous labetalol for blood pressure control in hypertensive emergencies in pregnancy.