A recent analysis published by CBC Health’s Second Opinion and authored by Lauren Pelley examined the ongoing scrutiny of a 2006 medical case report published in the peer-reviewed medical journal The Lancet. In January the New York Times published an investigative report by pulitzer-prize winning author Ben Taub reviewing the case. The study in the Lancet is by disgraced Motherisk lab founder, Gideon Koren and four other doctors (including one, James Cairns, who has surrendered his medical license, as Koren has also done). In the piece Korne et al. claim a baby died from opioid (codeine-derived morphine) poisoning transmitted through breast milk, and its results prompted widespread changes in global pain management practices and breastfeeding recommendations for new mothers.
The Lancet recently added an “expression of concern” to the study after “new allegations of falsification of toxicological data, authorship issues, and ethical concerns” were communicated to the journal in January. Although widely criticized, the study significantly influenced policy and practice, prompting government warnings, medication label changes, increased use of stronger opioids, and difficult choices for breastfeeding mothers.
Specifically, the case report described the 2005 death of an Ontario infant, attributing it to morphine transferred through breast milk after the mother was prescribed Tylenol 3. The medication contains acetaminophen and codeine, an opioid that is converted into morphine in the body, with some individuals metabolizing it more rapidly due to genetic variation. When Koren’s old colleague David Juurlink (Sunnybrook Hospital and U of Toronto pharmacologist) became aware of the questionable article he reviewed the case, including the confidential files of the coroner. These files showed that the child’s stomach actually contained a mass of unmetabolized codeine, showing hard evidence that the codeine came from a dose directly administered to the child, not from the mother’s milk as had been put forth by Koren et al.
For years, the study’s senior author Gideon Koren defended its conclusion that codeine taken by a breastfeeding mother could fatally harm an infant, despite growing criticism from other scientists. He later faced allegations of flawed or falsified research tied to the Motherisk lab at Toronto’s Hospital for Sick Children, whose drug-testing methods were deemed unreliable and used in criminal and child protection cases before the lab closed in 2019 and Koren relinquished his medical licence.
Juurlink’s evidence found in the review confirms that it was biologically implausible from breastfeeding, for the drug to have not been metabolized yet (as was found in the child’s stomach) it could only have been directly administered to the child. In addition, a second case that had been cited as corroborating evidence was later acknowledged by its author to have been fabricated for teaching purposes, without disclosure in the published version, yet it was presented and cited in the literature as a genuine clinical case.
Despite these concerns, the paper influenced public health guidance, prompting new breastfeeding pain-management guidelines and regulatory warnings in Canada and beyond. Although similar papers were retracted in 2020, The Lancet has referred new allegations to SickKids for investigation to determine whether further action, including possible retraction, is warranted.
In his interview with CBC News, the physician and assistant professor at the University of Toronto, Dr. Nav Persaud, questioned why The Lancet has not yet retracted the study, arguing that the issue should be resolved definitively, given longstanding concerns about its validity. Critics say the case was mishandled and that the findings are deeply flawed. Juurlink added that the study’s influence has shaped medical practice and public perception for years, leading some mothers to avoid breastfeeding out of fear of opioid-related harm.
