Chronic Prenatal Stress Shapes Neurodevelopmental Outcomes at Age Two Years Old.

Prenatal maternal stressors can heavily influence neurodevelopment. However, little is known about the effects of maternal chronic daily stress on postnatal neurodevelopmental milestones. This prospective case–control study assessed the development of 96 toddlers (M age = 2.26 years, SD = 0.31; 48% girls) using the Bayley Scales of Infant and Toddler Development–III, comparing children exposed to chronic maternal stress during the last trimester of pregnancy with non-exposed peers. Exposed children showed a lower mean composite language score (d = 0.48, p = .028), corresponding to a relative difference of 7.5%. No significant differences were found in cognitive (p = .126) or motor domain performance (p = .920). Given the role of early language skills in child development, reduced language scores may represent an early indicator of future developmental challenges. These findings highlight the importance of early detection and interventions aimed at reducing the long-term effects of chronic stress during pregnancy. This record contains the preprint version of the manuscript.