Postpartum maternal codeine therapy and the risk of adverse neonatal outcomes: a retrospective cohort study

To examine whether postpartum maternal prescription of codeine was associated with an increased risk of harm to newborns.

Population-based retrospective cohort study.

Ontario, Canada, from April 1, 1998 to March 1, 2008.

A total of 7804 mothers with publically-funded prescription drug coverage. Women who received a prescription for a codeine-containing product within 7 days following hospital discharge and their neonates were matched to 7804 mothers who did not receive codeine following delivery.

The primary outcome was readmission of the neonate to hospital for any reason within 30 days. Secondary outcomes included arrival to hospital by ambulance, hospitalization for dehydration, for injury, any hospitalization involving resuscitation or assisted ventilation, and all-cause mortality.

We studied 7804 infants whose mothers filled a prescription for codeine shortly after delivery and 7804 whose mothers did not. In the primary analysis, infants whose mothers received codeine were no more likely to be readmitted to hospital in the subsequent 30 days than children whose mothers did not (hazard ratio 0.95, 95% confidence interval (CI) 0.81-1.11). Moreover, we found no association between maternal codeine use and the other adverse neonatal outcomes studied. A stratified analysis revealed no differential risk among infants born by Caesarean section (hazard ratio 0.86; 95% CI 0.69-1.08).

In this large population-based study, maternal prescription of codeine following delivery was not associated with death or hospitalization in the early neonatal period.