Peripartum Synthetic Oxytocin Exposure and Breastfeeding Outcomes: An Integrative Review Update

A growing body of literature suggests that maternal exposure to synthetic oxytocin (SynOT) during labor, birth, or early postpartum may negatively affect newborn feeding behaviors and breastfeeding outcomes. However, a 2017 literature review reported mixed findings, highlighting the need for further investigation. Therefore, this integrative review aims to synthesize the most recent evidence on peripartum SynOT and breastfeeding outcomes.

A systematic search of Medline, CINAHL, and Web of Science was conducted for analytic studies published in English between 2015 and 2024. Included studies were synthesized in a literature matrix.

Eighteen studies from 13 countries met inclusion criteria (N = 607,062 participants). The proportion of measures that demonstrated a significant negative effect of intrapartum SynOT on a breastfeeding outcome varied by timing: 54.3% in the first 2 hours after birth, 43.5% between 2 hours and 1 week, 25.0% between 1 and 6 weeks, and 5.9% beyond 6 weeks. No positive effects were identified. Postpartum SynOT exposure was not associated with any measure. Multiple confounders were poorly accounted for, and only two studies conducted power analyses.

A clear temporal pattern emerged, with intrapartum SynOT more frequently associated with negative effects on newborn feeding behaviors and breastfeeding outcomes in the first week postpartum. This association remained, but at progressively lower rates, through 6 weeks and beyond. These findings suggest the need for early targeted lactation assistance for families undergoing induction or augmentation of labor with SynOT. Future research should address identified limitations, including sample size calculations and improved control for confounders.