Exogenous oxytocin used to induce labor has no long-term adverse effect on maternal-infant bonding: Findings from the Japan Environment and Children's Study.

Background: This study investigated the association between exogenous oxytocin use for labor induction and adverse maternal-infant bonding (MIB).

Methods: Data on 19 700 mother-infant pairs were collected, in which the infants were live-birth singletons, born in cephalic position and at >37 weeks of gestation; the drug used to induce labor was noted. Between 2011 and 2014, Japanese pregnant women were enrolled in a nationwide prospective birth cohort study, the Japan Environment and Children's Study. The Japanese version of the Mother-to-infant Bonding Scale (MIBS-J) was administered and demographic information was collected through medical record transcripts. MIBS-J scores were obtained at one month, six months, and one year after delivery. We estimated the risk of adverse MIB between use of oxytocin and other methods for labor induction using multiple linear regression analyses; interaction and mediation analyses to assess the relationship among MIBS-J scores also followed.

Results: Exogenous oxytocin was used during labor on 15 252 (77.4%) participants. After adjusting for confounders, there were no significant differences in adverse MIB between groups for which exogenous oxytocin was used and not used for labor induction.

Limitation: The MIBS-J scores at one and six months were compiled using five instead of 10 questions. Moreover, detailed information was unavailable; for example, the questionnaire did not ask for the dosage and timing of the drugs used to induce labor.

Conclusions: Exogenous oxytocin is a safe and vital drug to induce labor, and has been shown in this study to have no significant impact on long-term adverse MIB.