The efficacy of Massage+ on mother-infant synchrony in mothers with childhood adversity: A randomized controlled trial.

Parent-infant synchrony during social interaction exerts a critical influence on the healthy development of children. There is limited understanding of how synchrony may be influenced by mothers' history of childhood adversity. We evaluated the efficacy of a behavioral intervention, Massage+, on mother-infant synchrony among first-time mothers with childhood adversity. Adult pregnant women with adverse childhood experiences scores of ≥ 2 were enrolled in this longitudinal study. At birth, mothers and their full-term infants (N = 213) were randomized to the Massage+ group or the attention control group learning safe infant care. Mothers performed daily Massage+, which included talking to their infants, moderate touch stroking, looking at, and rocking their infant. At 3 months, mother-infant synchrony was microcoded for gaze, affect, vocalization, and touch from video recordings of a free-play interaction (N = 162). Compared with control dyads, the Massage+ dyads exhibited more co-occurring affect synchrony, touch synchrony, and maternal engagement with high infant arousal synchrony. Massage+ dyads also exhibited more sequential synchrony and faster time-to-first initiation of synchrony. When infants expressed positive arousal, Massage+ dyads were better able to increase the amount of synchrony, coordinate synchrony by mothers immediately responding to their infant's positive cues, and more quickly settle into synchrony. Encouraging positive affect is among the most critical early functions of synchrony. Future research warrants studying long-term benefits of Massage+ when implemented in real-world settings. (PsycInfo Database Record (c) 2026 APA, all rights reserved).