Abstract
Early language is shaped by parent-child interactions and has been examined in relation to maternal psychopathology and parenting stress. Minimal work has examined the relation between maternal emotion dysregulation and toddler vocabulary development. This longitudinal study examined associations between maternal emotion dysregulation prenatally, maternal everyday stress at 7 months postpartum, and toddler vocabulary at 18 months. Data were collected from 289 typically developing, monolingual children (54% female) and their mothers (63% White and non-Hispanic; 56% held a college degree). During pregnancy, maternal emotion dysregulation was measured via self-report and resting respiratory sinus arrhythmia (RSA). Mothers completed questionnaires about their perceived everyday stress and their child's vocabulary at 7 and 18 months postpartum, respectively. Path analysis revealed that expectant mothers' self-reported emotion dysregulation was indirectly associated with toddlers' expressive vocabulary via their level of postpartum perceived everyday stress. In addition, prenatal maternal resting RSA directly predicted toddlers' expressive vocabulary size. These findings yield insights into the mechanisms by which perinatal mental health may shape early language development and highlight the potential utility of interventions targeting emotion dysregulation during pregnancy.