Prospective Associations Between Maternal Interactive Style and Later Expressive Vocabulary in Preterm and Term-Born Children: A Two-Wave Longitudinal Study

Maternal interactive style may support early language, yet whether its dimensions relate differently to expressive vocabulary by birth status remains unclear. A two-wave longitudinal study included 149 Chinese mother–child dyads (59 preterm, 90 term; ages 9–30 months); 124 completed a four-month follow-up. Maternal interactive style was coded from free play, and mothers reported children’s expressive vocabulary. Principal component analysis yielded three components: Positive Interaction Support, Support for Autonomous Exploration, and Emotional-Affective Support. A Linear mixed model tested group differences in maternal interactive style, group-specific hierarchical regressions examined prospective associations adjusted for baseline vocabulary and covariates, and a pooled moderation regression tested birth-status interactions. Maternal interactive style differed significantly between groups, with no detectable group-by-dimension interaction. In the separate regression models, Positive Interaction Support was prospectively associated with later expressive vocabulary in both groups, Support for Autonomous Exploration did so in the term group, and Emotional-Affective Support was not significant in either group. In the pooled model, the Support for Autonomous Exploration × birth-status interaction was directionally consistent with this pattern but did not remain significant after Holm correction. These findings link specific components of maternal interactive style to later vocabulary, while whether these associations vary by birth status requires further investigation.