Use should be avoided during the first two trimesters of pregnancy; use is not recommended during the third trimester unless the benefit outweighs the risk to the fetus.

AU TGA pregnancy category: C
US FDA pregnancy category: C

Animal studies have revealed evidence of teratogenicity, including cleft palate and malformed facial and cranial bones at higher doses. There are no controlled data in human pregnancy.

AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

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During the first week postpartum, 10 lactating women had blood and breast milk samples analyzed 24 hours after receiving a dose between 10 and 40 mg. The average concentration of this drug plus its pharmacologically active acid-labile metabolites in breast milk was 240 nmol/L (about half of the simultaneous concentration in maternal plasma). It was further estimated that the daily dose to a breastfed infant was unlikely to exceed 25 mcg. Serum drug concentrations were measured in 2 infants 2 hours after feeding in this study and were determined to be 557 and 293 nmol/L.

Use is considered acceptable; according to some experts, use only if the benefit outweighs the potential risk.

Excreted into human milk: Yes

Comments: This drug has been used without apparent harmful effects in the nursing infant.

See references