Neurobehavioral disorders among children born to mothers exposed to illicit substances during pregnancy

Background: Exposure to illicit substances during pregnancy may have long-term impacts on children’s neurodevelopment. This study explores subsequent risks for intellectual disability, autistic disorders, and attention deficit and hyperactivity disorders in children born to mothers exposed to illicit substances before or during pregnancy. Methods: We identified women with illicit drug use by linking the police records from the “Substance Abuse Control Databases” and Taiwan Birth Registration and Birth Notification records from 2004 to 2014. Children whose mothers that had exposed to illicit substances during pregnancy identified from the police records were the “substance-exposed cohort.” A 1:1 ratio exact-matched comparison cohort based on child’s gender, child’s birth year, mother’s birth year, and child’s first use of the health insurance card, as well as a “propensity score (PS)-matched” comparison cohort of children born by substance-unexposed mothers, was established. Multivariate Cox regression analyses with competing risk models were performed. Results: Higher incidences of intellectual disability (adjusted hazard ratio (aHR) = 2.41, 95% confidence interval (CI): 1.15–5.03) and attention deficit and hyperactivity disorder (ADHD) (aHR = 2.35, 95% CI: 1.63–3.28) were found in children prenatally exposed to illicit substances during pregnancy compared to exact-matched non-exposed cohorts. Adjusted risks of ADHD were significantly higher in mothers exposed to substances during pregnancy (aHR = 1.77 (1.42–2.21)) and before pregnancy (aHR = 1.43 (1.14–1.80)) compared to PS-matched unexposed cohorts after adjusting for covariates. Conclusions: This is one of the first studies using large population-based data linked to criminal records to reveal increased risks of intellectual disability and ADHD in children with prenatal exposure to illicit substances compared to matched unexposed controls. Our results also highlight the importance of preventive measures and interventions for the well-being of both the mother and the child.