In rats, codeine has been shown to be embryolethal and fetotoxic at maternally toxic doses. In rats and rabbits administered doses ranging from 5 to 120 mg/kg during the period of organogenesis, teratogenicity was not observed. Prolonged use of opioids during pregnancy has resulted in babies born physically dependent. Opioids administered to mothers shortly before delivery may result in some degree of newborn respiratory depression, especially with higher doses. Limited data is available on guaifenesin use in pregnancy; although it does not appear to present a risk. There are no adequate and well-controlled studies in pregnant women.

Benefit should outweigh risk

US FDA pregnancy category: Not formally assigned a pregnancy category

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.
-Some liquid preparations contain alcohol.

See references

The US FDA recommends against use of prescription codeine pain and cough medicines in breastfeeding women. This is due to serious reactions in breastfed infants including excess sleepiness, difficultly breastfeeding, or serious breathing problems that could result in death. The US FDA is considering regulatory action for OTC combination cough and cold products containing codeine.

Codeine is present in breast milk and for women with normal codeine metabolism (normal CYP450 2D6 activity). The amount of codeine secreted is low and dose-dependent; however, in women who are ultra-rapid metabolizers of codeine (those with a specific CYP450 2D6 genotype) higher-than-expected serum levels of morphine (codeine's active metabolite) may be present in breast milk which may lead to dangerously high serum morphine levels in breastfed infants. In most cases, a person's specific CYP450 2D6 genotype is unknown. Several small series and 1 small retrospective study suggest that codeine may be causative in episodes of apnea, bradycardia, and cyanosis in the first week of life. A death of a breastfeed infant due to respiratory depression has been reported; the mother was found to be a CYP450 2D6 ultrarapid metabolizer.

Use is not recommended

Excreted into human milk: Yes (codeine); Unknown (guaifenesin)

Comments: Breastfeeding is not recommended when taking codeine due to the risk of serious adverse reactions in breastfed infants.

See references