Labetalol Pregnancy and Breastfeeding Warnings
Labetalol Pregnancy Warnings
Labetalol has been used for the treatment of hypertension during human pregnancy because of the paucity of adverse side effects on the fetus and neonate. Furthermore, labetalol does not appear to compromise uterine blood flow or inhibit uterine contractions despite an effective reduction in maternal systemic blood pressure. In one study of 42 women with moderate to severe pregnancy-induced hypertension, labetalol was an effective antihypertensive agent and did not significantly affect umbilical artery flow velocity. Three studies regarding the side effects or teratogenicity of labetalol are notable. Data from the Michigan Medicaid Birth Defects study have revealed an association between the use of labetalol and congenital abnormalities (written communication, Franz Rosa, MD, Food and Drug Administration, 1994). This was a retrospective study of 229,101 completed pregnancies between 1985 and 1992, of which 29 were exposed to labetalol at some time during the first trimester, and 143 were exposed to the drug at any time during pregnancy. Of the 29 pregnancies, there were 4 total birth defects (1 was expected). There were no observations of cardiovascular defects, cleft palate, spina bifida, polydactyly, limb reduction, or hypospadias. These data are consistent with an association between the use of labetalol and birth defects, although other factors, including underlying disease(s) of the mother are not accounted for. In one study, significantly more infants whose mothers received labetalol were growth retarded than in those infants whose mothers did not receive the drug. In another study, intrauterine growth retardation was detected in preeclamptic patients who had received labetalol. While labetalol crosses the placenta, side effects in the fetus or neonate are not expected. Rare cases of neonatal hypoglycemia, bradycardia, and hypotension have been reported and may be more likely with prolonged maternal labetalol treatment. The use of glucagon at doses of 300 to 600 mcg/kg have been suggested for treating neonatal low output congestive heart failure after maternal labetalol therapy.
Labetalol has been assigned to pregnancy category C by the FDA. Animal studies have failed to reveal evidence of teratogenicity, although an increased incidence of fetal resorption was demonstrated in some studies at doses approximating the maximum recommended human dose. There are no controlled data in human pregnancy. Labetalol should only be given during pregnancy when benefit outweighs risk.
Labetalol Breastfeeding Warnings
Labetalol is excreted into human milk in small amounts. Adverse effects in nursing infants are unlikely. Labetalol is considered compatible with breast-feeding by the American Academy of Pediatrics.
As with other beta-blockers, it is recommended that nursing infants who are potentially exposed to labetalol be observed for signs of beta-blockade during and immediately after breast-feeding. Signs of beta-blockade include bradycardia and hypotension.
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