At usual doses, labetalol is considered compatible with breastfeeding.
Beta-blockers have an increased risk of passing to milk and accumulate in the child, when the lower be the percentage of plasma protein binding and greater the degree of renal excretion, which goes parallel to the free fraction of drug in the blood. In this case, labetalol is of medium-low risk for the baby by its pharmacokinetic characteristics (5% renal elimination, 50% protein binding), so it should only be avoided in mothers of preterm infants.
It is considered that an infant can ingest an average amount of 0.004% to 0.07% of the dose given to the mother. It has been described a case of bradycardia in a premature baby whose mother took 300 mg twice daily of labetalol.
Warning of the manufacturer:
Labetalol crosses the placental barrier and can block alpha and beta-adrenergic receptors of the fetus and newborn. Very rarely described perinatal and neonatal abnormalities (bradycardia, hypotension, respiratory depression, hypoglycemia, hypothermia). Sometimes these symptoms develop a day or two after birth. The response to supportive measures (eg, intravenous fluids and glucose) is generally fast, but in case of severe preeclampsia, especially after prolonged treatment with intravenous labetalol, recovery may be slower. This may be associated with decreased hepatic metabolism in premature infants. P>
It have been described stillbirths, neonatal intrauterine growth retardation and preterm delivery, although were also involved the effects of pre-eclampsia and other drugs (eg vasodilators, respiratory center depressants). This clinical experience warns against unduly prolonged use of high doses of labetalol and delayed delivery, and against coadministration of hydralazine.
This medicine is excreted in breast milk, although no adverse effects have been reported in children and infants.