Association between labetalol use for hypertension in pregnancy and adverse infant outcomes

Labetalol and methyldopa are the two antihypertensive drugs most frequently used to control blood pressure for hypertensive disorders of pregnancy. The objective of this study was to assess if labetalol is associated with poor infant outcomes.

Retrospective population-based cohort study using the linked maternal/infant databases in the Province of Saskatchewan. Women with a diagnosis of a hypertensive disorder of pregnancy who delivered a singleton in Saskatchewan from January 1, 1990 to December 31, 2005 and who were dispensed only labetalol or only methyldopa were included in the study. Occurrences of small for gestational age (SGA)<10th percentile, SGA<3rd percentile, preterm birth, stillbirth, hospitalization for respiratory distress syndrome (RDS), sepsis, and seizure during infancy, and infant death were compared. Multiple logistic regression analysis was performed to adjust for potential confounding.

A total of 1223 eligible women were included in the final analysis. Among them, 300 received labetalol only and 923 received methyldopa only during pregnancy. For women with chronic hypertension, the rate of hospitalization for RDS, sepsis, and seizure during infancy was significantly higher for infants born to mothers who were dispensed labetalol only as compared with infants born to mothers who were dispensed methyldopa only (adjusted odds ratio (OR) 1.51, 95% confidence interval (CI) 1.02-2.22).

Compared with methyldopa, the use of labetalol for chronic hypertension of pregnancy may be associated with increased rate of hospitalization during infancy.