Synthetic oxytocin induction linked to poorer early mother-infant bonding, but not long-term, in large Japanese cohort
Background
Early mother-to-infant bonding is crucial for child development and maternal well-being, yet its establishment can be influenced by peripartum factors. Labor induction, often using synthetic oxytocin (synOT) or prostaglandins (PG), has become increasingly common. These exogenous agents may disrupt the natural pulsatile release of endogenous oxytocin, a key hormone in bonding and lactation, potentially affecting maternal physiology and early breastfeeding initiation. Understanding these implications is vital given the widespread use of induction and the long-term impact of bonding on family health.
Study Design
Researchers analyzed data from the Japan Environment and Children's Study (JECS), including 58,384 mother-infant dyads from liveborn, term, singleton vaginal deliveries. Mother-to-infant bonding was assessed using mothers' self-reported feelings via the Mother-to-Infant Bonding Scale (MIBS) at 1, 6, and 12 months postpartum. Labor induction status and specific agents (synOT, PG) were extracted from medical records. Linear mixed-effects models were used to test associations with bonding trajectories, and mediation analyses evaluated the role of 1-month feeding mode (exclusive formula vs. any breastfeeding) in observed associations.
Results
Labor induction was associated with a time-varying pattern in mother-to-infant bonding (time × induction: β = -0.057, 95% CI [-0.067, -0.046], p < 0.001). While overall contrasts at 1, 6, and 12 months were not significant, specific induction agents showed clearer effects. Synthetic oxytocin (synOT) exposure was significantly associated with poorer bonding at 1 month (β = 0.027, p = 0.004) and 6 months (β = 0.016, p = 0.024), although this association did not persist by 12 months (β = 0.010, p = 0.205). Mediation analysis indicated that the influence of 1-month feeding mode (exclusive formula vs. any breastfeeding) on these associations was minimal.
The indirect effect via feeding was small for overall induction (indirect effect = 0.001, 95% CI [0.0002, 0.001]) and not substantially supported for synOT (indirect effect = 0.0004, 95% CI [-0.00009, 0.001]), suggesting other mechanisms are at play.
Key Findings
- Labor induction was associated with a time-varying pattern in mother-to-infant bonding (p < 0.001).
- Synthetic oxytocin exposure was linked to poorer bonding at 1 month (p = 0.004) and 6 months (p = 0.024).
- The association between synthetic oxytocin and poorer bonding did not persist at 12 months postpartum.
- Mediation by 1-month feeding mode (breastfeeding vs. formula) was small for induction (indirect effect = 0.001).
Why It Matters
This large-scale study suggests that labor induction, particularly with synthetic oxytocin, may transiently impair early mother-to-infant bonding. For clinicians, this highlights the importance of providing enhanced postnatal support and screening for bonding difficulties in mothers who undergo induced labor. While breastfeeding is often linked to bonding, its mediating role here was found to be small, indicating that the physiological impact of exogenous oxytocin on the maternal neuroendocrine system or the birth experience itself may be more dominant. Future protocols might consider strategies to mitigate these early bonding challenges, such as immediate skin-to-skin contact or targeted psychological support, especially in the first six months postpartum.
oxytocin
labor-induction
maternal-bonding
postpartum
breastfeeding
cohort-study