Non-pulsatile oxytocin given during labour can negatively affect breastfeeding. The aim of this study was to assess whether intrapartum oxytocin administration has any effect on breastfeeding. Secondly, to assess whether some maternal or neonatal variables influence breastfeeding. A retrospective cohort study was done, comparing two groups: women exposed (n = 101) and not exposed to oxytocin (n = 100) during labour. Women with caesarean section, vacuum extraction/forceps, twin pregnancy, breech presentation, premature neonates and with an Apgar score <7 at 5 minutes were excluded. Duration of breastfeeding was evaluated by a phone call interview. A regression analysis was done, evaluating possible confounding factors. The use of oxytocin during labour was demonstrated to be a predictor of impaired first hour breastfeeding (OR =2.493, CI: 1.05-5.92; p = .038). At three months' postpartum, 26.7% women in the exposed group versus 14% in the non-exposed group were not breastfeeding (p = .035). This result was not statistically significant when adjusting for possible confounders. High pregestational body mass index was the best predictor of an impaired third month's postpartum breastfeeding (OR =0.901, CI: 0.835-0.972; p = .007). Intrapartum oxytocin administration could inhibit first hour breastfeeding. A novel association was detected, pregestational body mass index was a predictor of impaired breastfeeding at three months, possibly confounding the oxytocin effect. Additional prospective studies are needed to investigate potential associations between intrapartum oxytocin and breastfeeding. Impact statement What is already known on this subject? Oxytocin is a common medical intervention during labour. Some studies suggest a negative association between intrapartum oxytocin dose, newborn sucking and an increased risk of early breastfeeding discontinuation. However, some maternal variables were not considered in these studies and the impact synthetic oxytocin may have on breastfeeding has not been thoroughly researched. What do the results of this study add? In this study, intrapartum oxytocin administration seems to inhibit the first hour breastfeeding. However, a novel association was detected, high pregestational body mass index was a predictor of impaired breastfeeding at three months, possibly confounding oxytocin effects. What are the implications of these findings for clinical practice and/or further research? Additional prospective studies are needed to investigate potential associations between intrapartum oxytocin and breastfeeding. Therefore, health care professionals should help obese women, starting from conception, to maximise breastfeeding outcomes as much as possible.
Keywords: Body mass index; breastfeeding; education level; labour; oxytocin; weight gain.