Reproduction studies in mice, rats, and rabbits during organogenesis have not revealed evidence of teratogenicity, however, rats receiving butorphanol 1 mg/kg had a higher frequency of stillbirths than controls and rabbits receiving oral doses of 30 and 60 mg/kg showed higher incidences of post implantation loss. Prolonged use of opioid analgesics during pregnancy may cause neonatal opioid withdrawal syndrome. This drug is not recommended for use during or immediately prior to labor, when other analgesic techniques are more appropriate. There are no controlled data in human pregnancy.

Chronic opioid use may cause reduced fertility in males and females; it is unknown whether these effects on fertility are reversible.

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.

Benefit should outweigh risk

US FDA pregnancy category: C

Comments:
-Prolonged use of opioids during pregnancy can result in physical dependence in the neonate; women should be advised of the risk of neonatal abstinence syndrome and ensure that appropriate treatment will be available.

See references

This drug is excreted into breastmilk in small amounts. It is poorly absorbed (adult oral bioavailability is estimated at 17%) so it is unlikely to adversely affect the breastfed infant. However, there is limited published data with repeated, high, IV or intranasal doses in breastfed infants. If used, extra caution is advised in newborn or preterm infants.

Benefit should outweigh risk

Excreted into human milk: Yes

Comment:
-Monitor closely for excess sedation, breathing difficulties, or limpness; mothers should be instructed to seek immediate medical care if these signs develop.

See references