Background Little is known about how breastfeeding rates are affected by drugs routinely administered in labour.
Objective To examine a large obstetric data set to investigate potentially modifiable associations between drugs routinely administered in labour and breastfeeding in healthy women and infants.
Design Retrospective cohort.
Setting The Cardiff (Wales UK) Births Survey.
Population A total of 48 366 healthy women delivering healthy singleton babies at term.
Methods Analysis of the Cardiff Births Survey.
Main outcome measure Association between intrapartum medications and breastfeeding at 48 hours postpartum.
Results At 48 hours, 43.3% (20 933/48 366) women were not breastfeeding. Regression analysis confirmed previously reported associations of lower breastfeeding rates with certain demographic indicators, epidural analgesia, intramuscular opioid analgesia and ergometrine. Novel associations were detected with oxytocin alone or in combination with ergometrine administered for prevention of postpartum haemorrhage (PPH), which were associated with reductions of 6–8%, (intramuscular oxytocin OR 0.75, 95% CI 0.61–0.91, intravenous oxytocin OR 0.68, 95% CI 0.57–0.82, oxytocin/ergometrine OR 0.77, 95% CI 0.65–0.91), and prostaglandins administered for induction of labour. The associations were maintained when subgroups, such as primiparous women, women whose labours were neither induced nor augmented, and women not receiving epidural analgesia were considered.
Conclusion Prospective studies on drugs in labour are needed to investigate potential causative associations between intrapartum medications and breastfeeding. Such studies will delineate the optimum balance between breastfeeding and maternal health, most importantly the risk of PPH.