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.