A controversial medical paper has sparked a global debate, and its influence is still being felt, even after two decades. The paper, published in Canada, claimed a tragic infant death was due to codeine poisoning through breast milk, but this claim is now under intense scrutiny.
The Lancet, a renowned medical journal, has added an "expression of concern" to the 2006 case report, highlighting new allegations of data falsification and ethical concerns. This move follows a year-long investigation by The New Yorker and years of media coverage in Canada.
Despite being widely debunked by researchers, this single case study has had a profound impact. It has led to government warnings, changes in medication labels, and a shift towards more potent and addictive opioids. Many women have faced a difficult choice between pain relief and breastfeeding their newborns.
The Lancet case study focused on an infant poisoning incident in Ontario in 2005. It suggested the baby's mother, who was prescribed Tylenol 3, passed a lethal dose of morphine to her son through breast milk. This combination drug, commonly used for postpartum pain management, contains acetaminophen and codeine, which is partially metabolized into morphine in the body. Some individuals, like the mother in this case, have a genetic predisposition to convert codeine faster and in larger amounts.
The author, Gideon Koren, once revered as the founder of the now-shuttered Motherisk drug testing lab, has faced numerous allegations of flawed or falsified study findings. The Motherisk lab, initially praised for its innovative hair testing for drug and alcohol use in mothers, was later deemed "inadequate and unreliable" by an independent review in 2015. Its discredited tests were used in criminal and child protection cases, often leading to the separation of children from their families.
Many critics argue that Koren's most influential finding, from the 2006 Lancet case study, is simply impossible and should be fully retracted. David Juurlink, a renowned Canadian pharmacologist and toxicologist, recalls believing Koren's narrative for a few years but soon became unsettled by the study's results. He has since raised concerns, stating that the report falls apart under scrutiny.
Juurlink and others argue that Koren misinterpreted the toxicology results and failed to recognize that the extremely high concentrations of acetaminophen and codeine in the infant's bloodwork are "impossible consequences" of breastfeeding. The postmortem examination showed codeine in the baby's stomach, but no morphine, suggesting direct administration of the drug.
Despite these concerns, Koren's paper has had a lasting impact on global public health messaging. In 2008, Canada's top pediatricians and obstetricians began developing new guidelines on safe painkillers during breastfeeding, and Health Canada issued warnings for nursing mothers. Two Canadian medical journals retracted similar papers by Koren in 2020, following Juurlink's concerns.
The Lancet has referred the latest allegations about Koren's paper to SickKids' research integrity office for a new investigation. A spokesperson for the hospital has stated that SickKids will meet with the journal and initiate a formal review if necessary.
Dr. Nav Persaud, an assistant professor at the University of Toronto and a critic of Koren's research, questions the Lancet's delay in retracting the paper. He believes this issue needs to be addressed definitively, as it started with the tragic death of a newborn and the investigation has been mishandled.
Juurlink emphasizes that Koren's influence has led to a generation believing that breastfeeding mothers taking prescribed opioids can harm or even kill their babies. He worries that this myth has caused many mothers to avoid breastfeeding altogether, missing out on its benefits.
"It's basically a myth, and it all goes back to one sloppy misreading of a single case 20 years ago," Juurlink said.
This story highlights the importance of scientific integrity and the potential consequences when a single study, later found to be unreliable, can shape global health guidance.
