A causal moderated mediation analysis of maternal prenatal bonding and daily infant engagement on postpartum bonding.

BACKGROUND: The early maternal-infant bond has profound impacts for infant development. Prior research indicates that higher self-reported maternal-fetal bonding predicts greater postpartum bonding, but additional research is needed on the mechanisms that may promote the early maternal-infant relationship. We explored daily engagement in caregiving behaviors as a potential non-pharmacological intervention to promote maternal and infant health. METHODS: This study utilizes a diverse and predominately low-income sample of 114 mothers of infants who were recruited at their first prenatal visit in 2017-2018 and followed through at least six months post-birth. We conducted a causal mediation analysis to examine whether daily engagement at two months postpartum functions as a mediator in the maternal prenatal and postpartum bonding relationship, and additionally tested whether this mediation was moderated by maternal prenatal bonding levels for postpartum bonding. RESULTS: Maternal prenatal bonding was associated with daily engagement (b = 0.03, SE = 0.01, p < .001) and postpartum bonding (b = 0.28, SE = 0.08, p = .001), controlling for covariates. We also found that daily engagement at two months postpartum was associated with bonding at six months postpartum (b = 3.88, SE = .95, p < .001). Causal mediation analyses indicated a significant indirect effect of prenatal bonding on postpartum bonding through daily engagement among mothers with lower levels of prenatal bonding. There was also evidence of moderation; daily engagement was a stronger predictor of postpartum bonding among mothers with lower prenatal bonding, whereas mothers with higher prenatal bonding showed consistently strong bonding regardless of engagement level (adjusted R2 = .378). CONCLUSIONS: The results of this study indicate that maternal engagement activities may help to facilitate postpartum bonding and may explain the association between prenatal and postpartum bonding. Additionally, engaging in more caregiving activities may strengthen postpartum bonding, particularly among those with lower prenatal bonding. These findings suggest promoting maternal engagement in caregiving behaviors may promote a stronger postpartum bond.