An estimated 80 percent of North American mothers breastfeed their babies. New research out of Canada suggests some mothers who take medicines which contain codeine may be inadvertently harming their breastfed infants. The study done at the University of Western Ontario indicates some women have a rare genetic predisposition to metabolize codeine-laced drugs into morphine faster than normal.
The condition means morphine gets passed through the mother and can harm a nursing infant's central nervous system.
Doctors say the threat of overdosing the baby appears reversible if the mother stops taking the medication.
The study's findings are published in the online issue of Clinical Pharmacology and Therapeutics.