Comparing Intravenous Labetalol and Intravenous Hydralazine for Managing Severe Gestational Hypertension

Background Hypertensive disorders of pregnancy are the leading causes of both maternal morbidity and maternal mortality. Hypertensive disorders are acute obstetric emergencies, which refer to various life-threatening medical challenges known to develop during pregnancy, labor, and delivery, requiring urgent attention to reduce blood pressure (BP) for the benefit of the affected mothers and infants. Hydralazine and labetalol have been widely used as the first-line medications in the management of severe hypertension during pregnancy. However, the choice between these two drugs lacks clear evidence regarding their safety and superiority. Several studies have attempted to study intravenous (IV) labetalol versus hydralazine, but very few such comparison studies have been conducted in Africa.  Objective To compare the effectiveness of IV labetalol and IV hydralazine in reducing systolic and diastolic BP in pregnant women with severe hypertension. Also, to determine the time required for hydralazine and labetalol to lower BP to ≤150/100 mmHg, the number of doses needed for each drug, and evaluating maternal and perinatal outcomes. Study design This study employed an open-label randomized clinical trial design conducted in the labor, delivery, and antenatal ward of the Central and Stella Obasanjo Hospital in Benin City. A total of 120 women with severe pregnancy-induced hypertension were randomly assigned to two groups: Group X, consisting of 60 pregnant women, received IV hydralazine at a slow rate of 5 mg for five minutes, repeated every 20 minutes (maximum of five doses) until a blood pressure of ≤150/100 mmHg was achieved. Group Y, also consisting of 60 pregnant women, received IV labetalol in escalating doses of 25, 50, 75, 75, and 75 mg (maximum of 300 mg) every 20 minutes until the blood pressure reached ≤150/100 mmHg. Statistical analysis was performed using SPSS version 23 (IBM Inc., Armonk, New York). Result IV hydralazine achieved the target BP in an average time of 45.80 +/- 25.17 minutes, while IV labetalol took an average of 72.67 +/- 41.80 minutes (p=0.001). The number of doses required to reach the target BP differed significantly between the two drugs. Hydralazine required an average of 1.72 +/- 0.904 doses, whereas labetalol required an average of 3.72 +/- 1.782 doses (p=0.0001). While 45% of women in the hydralazine group attained the target BP with a single dose of hydralazine, only 31.1% of women in the labetalol group were able to attain the target BP with a single dose of labetalol (p=0.02). Overall, target BP was achieved in 55 out of 60 women (91.7%) who were randomized to receive IV hydralazine, whereas 45 out of 60 women (75%) who received IV labetalol achieved the target blood pressure. While hydralazine demonstrated more favorable results in terms of achieving target blood pressure, there were higher incidences of maternal adverse effects in the hydralazine group compared to the labetalol group. However, these adverse effects were not severe enough to warrant discontinuation of the medication. Conclusion IV hydralazine showed faster achievement of the target BP and a lower number of doses required compared to IV labetalol. Additionally, a higher percentage of women in the hydralazine group achieved the target BP with a single dose. However, there were more maternal adverse effects associated with hydralazine, although they were not severe. Perinatal outcomes did not differ significantly between the two groups.