Although no teratogenic effects have been demonstrated in animals, Labetalol hydrochloride should only be used during the first trimester of pregnancy if the potential benefit outweighs the potential risk.
In humans, Labetalol crosses the placental barrier and the possibility of the consequences of alpha- and beta-adrenoceptor blockade in the fetus and neonate should be borne in mind. Perinatal and neonatal distress (bradycardia, hypotension, respiratory depression, hypoglycaemia, hypothermia) has been rarely reported. Sometimes these symptoms developed a day or two after birth. Response to supportive measure (e.g.i.v. fluids and glucose) is usually prompt but with severe preeclampsia, particularly after prolonged i.v. Labetalol hydrochloride, recovery may be slower. This may be related to diminished liver metabolism in premature babies. Intra-uterine and neonatal deaths have been reported but other drugs (e.g. vasodilators, respiratory depressants) and the effects of pre-eclampsia, intra- uterine growth retardation and prematurity were implicated. Such clinical experience warns against unduly prolonging high dose Labetalol hydrochloride and delaying delivery and against co-administration of Hydralazine.
Labetalol is excreted in breast milk: no adverse effects in breast feeding infants have been reported.