A new large Canadian study just published in the British Medical Journal gives reassurance that opioid drugs taken by mothers will not harm breastfed babies.
All opioid drugs pass into breast milk but in very small quantities not expected to cause any harm. There has been a question about babies being affected by opioid drugs in breast milk since a report was published in 2006 which reported that a breastfed baby had come to harm after the mother had been taking the opioid drug codeine. This led to governments in the USA and UK advising against the use of codeine by women who were breast feeding. This report has since been discredited and retracted, although government guidance is yet to change.
Codeine is converted by the body to morphine but, unlike other opioid drugs, there's variation in how well people are able to convert codeine to morphine. Some people convert it fast, while other people cannot convert it and find codeine to be an ineffective painkiller.
Because of this variability, many women are prescribed other opioids for pain relief after childbirth. This is likely to continue, but this new study can provide reassurance that women can continue to use prescribed opioid painkillers after childbirth, if needed, without the worry that their breastfed babies will be harmed.
