A comparative study of efficacy of antihypertensive drugs andfeto-maternal outcome in the treatment of pregnancy induced hypertension

Abstract

Background: Hypertensive disorders are the most common medical disorders in pregnancy contributing significantly to maternal and perinatal mortality and morbidity worldwide. The incidence is around 3-10% of all pregnancies. The aim of antihypertensives is to reduce, stabilize the blood pressure and thus minimize the risks such as placental abruption, maternal cardiac failure, cerebral hemorrhage; but they should not have any adverse effects on the utero-placental circulation and the fetus. Antihypertensive drugs are often used to lower blood pressure to prevent this progression to adverse outcomes for the mother and the fetus. The risk of developing severe hypertension is reduced to half by using antihypertensive medications. The aim and objectives of the study was a comparative study of the efficacy of methyldopa, nifedipine versus labetalol and the feto-maternal outcome in gestational hypertension in a tertiary care referral centre. Methods: A prospective study on 240 outpatients as well as inpatients of the antenatal ward of Obstetrics and Gynaecology department of Chhattisgarh Institute of Medical Sciences, Bilaspur which is a tertiary care referral hospital. The patients randomly divided in three groups. The first group received alpha-methyl dopa 250mg tds, second 20 mg bd nifedipine and the third one labetalol 100mg bd. Mean arterial pressure calculated by systolic BP +2 DBP/3.The fall in BP calculated along with time required, dose of drug required, spontaneous/ induced labour or caesarean section, adverse maternal and the fetal outcome was observed. Results: Maximum number of patients that is 145(60.42%) patients belonged to the age group of 19 to 24 years and were primigravida (70.42%) presenting at 33-37 weeks of gestation. Significant fall in MAP was seen in patients receiving nifedipine and labetalol. Mean time to control blood pressure is 46.32 hrs in methyldopa group, 30.44hrs in nifedipine group and 37.24 hrs in labetalol group. 103 (42.9%) patients had normal delivery whereas 137 (57.1%) required a caesarian section, higher rate of spontaneous labour in nifedipine and labetalol group. Most common side-effect observed was headache; the other side effects included drowsiness, more in patients treated with methyldopa, weakness, more in patients treated with labetalol. The fetal outcome was better with labetalol and nifedipine than methyl-dopa group. Conclusions: The decreased association from maternal and fetal side-effects, the comparatively better hypotensive action indicates that labetalol and nifedipine is suitable for use during pregnancy. Labetalol is safer, quicker in achieving adequate control of blood pressure with considerable prolongation of the duration of pregnancy with fewer side effects on the mother as well as the neonate when used in the management hypertensive disorders of pregnancy.