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No serious risk to infants born to people prescribed opioids after birth, study finds


Infants born to people prescribed opioids after delivery are at no greater risk of hospital readmission or other serious outcomes than infants not exposed to opioids, according to a new study from ICES and Sunnybrook Health Sciences Centre.

Opioids are sometimes prescribed to treat pain in people who have recently given birth, especially for those who give birth by cesarean section. Treatment of postpartum pain can improve outcomes for babies and parent-infant bonding. However, concerns have been raised about opioid toxicity in breastfed infants.

“We know that infants can be exposed to small amounts of opioids that pass through breast milk,” says lead author Jonathan Zipursky, staff physician in general internal medicine and clinical pharmacology and toxicology at Sunnybrook Health Sciences Centre, and adjunct scientist with ICES and Sunnybrook Research Institute. “Although there have been isolated reports of harms from opioids for breastfed infants, there is uncertainty over whether the amount passing into breast milk is enough to cause serious respiratory or central nervous system issues.”

Researchers used population health data from ICES and included 865 691 parent-infant pairs discharged from hospital seven days after delivery from September 2012 to March 2020. Individuals who filled an opioid prescription within seven days of discharge were matched to individuals who did not.

The study, published in BMJ, found that:

  • Of the infants admitted to hospital within 30 days of birth, 2962 (3.5%) were born to people who filled an opioid prescription compared to 3038 (3.5%) born to people who did not fill a prescription.
  • Infants of people prescribed an opioid were no more likely to be admitted to hospital for any reason than infants of people who were not prescribed an opioid.
  • Infants exposed to opioids had a small increased absolute risk (0.41%) of visiting an emergency department in the 30 days following delivery.
  • There were no significant differences between the groups for a number of other adverse health outcomes, including admission to the NICU, mechanical ventilation, or infant death.

One limitation of the study is that breastfeeding status could not be assessed. However, previous research has shown that more than 80% of new parents attempt breastfeeding in North America. For this reason, a short follow-up period of 30 days was chosen to account for higher breastfeeding rates in the first month postpartum.

“Our findings aren’t meant to encourage the use of opioids after birth. But opioids are sometimes necessary during breastfeeding, and our findings offer a measure of reassurance to patients and doctors that the practice poses little risk to infants,” says senior author David Juurlink, staff internist and head of the division of clinical pharmacology and toxicology at Sunnybrook Health Sciences Centre and senior scientist with ICES and Sunnybrook Research Institute. “Evidence-based guidelines for postpartum pain management would help providers assess the need for opioids.”

The study, “Maternal opioid treatment after delivery and risk of adverse infant outcomes: population based cohort study” was published in BMJ.

Author block: Zipursky J, Gomes T, Everett K, Calzavara A, Paterson M, Austin P, Mamdani M, Ray J, Juurlink D.

ICES is an independent, non-profit research institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. In October 2018, the institute formerly known as the Institute for Clinical Evaluative Sciences formally adopted the initialism ICES as its official name. For the latest ICES news, follow us on Twitter: @ICESOntario

Sunnybrook Health Sciences Centre
is inventing the future of healthcare for the 1.3 million patients the hospital cares for each year through the dedication of its more than 10,000 staff and volunteers. An internationally recognized leader in research and education and a full affiliation with the University of Toronto distinguishes Sunnybrook as one of Canada’s premier academic health sciences centres. Sunnybrook specializes in caring for high-risk pregnancies, critically-ill newborns and adults, offering specialized rehabilitation and treating and preventing cancer, cardiovascular disease, neurological and psychiatric disorders, orthopaedic and arthritic conditions and traumatic injuries. The Hospital also has a unique and national leading program for the care of Canada’s war veterans. www.sunnybrook.ca


Misty Pratt
Senior Communications Officer, ICES
[email protected]

Marie Sanderson
Communications Advisor
Sunnybrook Health Sciences Centre
[email protected]


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