Perinatal risk factors and infantile autism

Objective: Suboptimal conditions during pregnancy and birth have been suggested as a cause of infantile autism. We have studied the association between obstetric factors and infantile autism. Method: A population-based, matched case-control study of infantile autism. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI). Results: The risk of infantile autism was increased for mothers aged > 35 years, with foreign citizenship, and mothers who used medicine during pregnancy. A higher risk of infantile autism was seen among children with low birth weight and with congenital malformations. Birth interventions, pathological cardiotocography, green amnion fluid and acidosis during delivery were not associated with increased risk for infantile autism. Conclusion: Our findings suggest that suboptimal birth conditions are not an independent risk factor for infantile autism. A high prevalence of low birth weight and birth defects among autism cases seems to explain the suboptimal birth outcome.