AU and UK: Use is not recommended
US: This drug should be used during pregnancy only if the benefit outweighs the potential risks to the fetus.

AU TGA pregnancy category: B1
US FDA pregnancy category: C

Animal studies have revealed evidence of reproductive toxicity where systemic exposures of this drug were several times higher than the therapeutic exposure level. There is theoretical potential that this drug may precipitate opioid withdrawal in a fetus. There are no controlled data in human pregnancy.

AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.

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.

See references

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Unknown
Excreted into animal milk: Yes

Comments:
-This drug is not recommended in nursing mother of infants less than 6 months old due to a theoretical possibility that this drug could provoke opioid withdrawal in a breastfed infant whose mother is taking an opioid receptor agonist.
-For infants greater than 6 months of age, a decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

See references