Longitudinal effects of contextual and proximal factors on mother-infant interactions among Brazilian adolescent mothers

• Mother’s social support at 3 months had an indirect effect on infant behaviors at 6 months.
• Infant behaviors at 6 months totally mediated by maternal behavior at 6 months.
• Longitudinal process involved in both maternal and infant behaviors.

Adolescent mothers often come from vulnerable backgrounds which might impact the quality of both maternal and infant behavior. Despite the negative impact of adolescent motherhood for maternal and infant behavior, social support may decrease the risks and promote maternal behavior toward the infant. The aim of this study was to investigate longitudinally the effects of proximal (maternal behavior) and distal (mother’s perceived social support) variables on infant development in a sample of Brazilian adolescent mothers and their infants. Thirty-nine adolescent mothers (Mage = 17.26 years; SD = 1.71) were observed interacting with their infants at 3 and 6 months postpartum and reported on social support. Results revealed that maternal and infant behavior were associated within and across times. Mothers’ perceived social support at 3 months had an indirect effect on infant behavior at 6 months, totally mediated by maternal behavior at 6 months. Our findings revealed the mutual influence between maternal and infant behavior, revealing a proximal process. The results also underscored the importance of the passage of time in the interplay between mother-infant interactions and their developmental context.