Prenatal substance exposure and developmental outcomes at age 5: a population-based cohort of 260 000 children in New South Wales, Australia.

OBJECTIVES: We quantified the risk of developmental support needs at school entry among children with and without prenatal substance exposure, to inform service delivery initiatives in the first 2000 days of children's lives. METHODS: We assembled a cohort using population-level perinatal, birth registration, hospital and education data linked for the New South Wales Child E-Cohort. Children born 2008-2014, with Australian Early Development Census data collected 2015, 2018, 2021 (n=262 968), were grouped into children with and without prenatal substance exposure (using indicators in mother/child hospital, emergency department, mental health outpatient, opioid treatment and/or child protection report data). We quantified the risk of developmental support needs, including teacher-reported developmental vulnerability on ≥1 of five domains or medically diagnosed conditions with support needs at school entry. RESULTS: Half of prenatal substance-exposed children (n=4306) had developmental vulnerability on ≥1 domains or ≥1 medically diagnosed conditions at school entry, compared with 24% of all other children. Developmental vulnerability on ≥2 domains was more common among prenatal substance-exposed children (24%) than all other children (9%). 11% of prenatal substance-exposed children had ≥1 medically diagnosed conditions, versus 5% of all other children. Autism spectrum disorder, attention deficit hyperactivity disorder, global developmental delay and fetal alcohol spectrum disorder were the most common conditions among prenatal substance-exposed children. CONCLUSIONS: Half of prenatal substance-exposed children had developmental support needs during the first 2000 days of life, highlighting the importance of interagency prevention responses spanning substance use in pregnancy services through to the postnatal and early childhood support services for affected children.