Oxytocin administered during labor and breast-feeding: a retrospective cohort study

Objective: The relationship between labor physiology and the onset of lactation leads to assess the potential correlation between oxytocin administration during labor and duration of breast-feeding. Methods: This study was designed as a retrospective cohort study where patients given synthetic oxytocin during labor induction were considered as the exposed cohort, and patients not given oxytocin formed the non-exposed cohort. Four hundred of the 7465 children born at our maternity during 2006 were randomly selected. Information about breast-feeding was available for 316 of these children. Eventual confounding or adjustment factors were analyzed using stratified and multivariate analysis. Results: Oxytocin was used for delivery of 189 (59.8%) newborns, multiplying the risk of bottle-feeding by 1.451 (95% CI 1.28-1.63). The best-fit regression model of oxytocin use effect on bottle-feeding included sex and gestational age of the newborn. The use of oxytocin also multiplies the risk of breast-feeding withdrawal at 3 months by 2.29 (95% CI 1.41-3.74). This effect is confounded by maternal age, being higher for mothers under 27 years. Conclusion: Oxytocin administration during labor had some impact on both onset and duration of breast-feeding, particularly in mothers under 27 years of age and newborns delivered at term. Clinical Study registered at U. S. NIH, ID: NCT01951040.