This study investigates the association between prenatal exposure to valproate and the risk of autism spectrum disorders (ASDs) and childhood autism. Using a population-based cohort of children born in Denmark from 1996 to 2006, researchers identified 5437 cases of ASD and 2067 cases of childhood autism. The study found that children whose mothers used valproate during pregnancy had a significantly higher risk of ASD and childhood autism compared to those whose mothers did not use valproate. The adjusted hazard ratios (HRs) for ASD and childhood autism were 2.9 (95% CI, 1.7-4.9) and 5.2 (95% CI, 2.7-10.0), respectively. These findings were consistent even after adjusting for maternal epilepsy and other confounders. The study concludes that maternal use of valproate during pregnancy is associated with a significantly increased risk of ASD and childhood autism, highlighting the need for caution in its use among women of childbearing potential.This study investigates the association between prenatal exposure to valproate and the risk of autism spectrum disorders (ASDs) and childhood autism. Using a population-based cohort of children born in Denmark from 1996 to 2006, researchers identified 5437 cases of ASD and 2067 cases of childhood autism. The study found that children whose mothers used valproate during pregnancy had a significantly higher risk of ASD and childhood autism compared to those whose mothers did not use valproate. The adjusted hazard ratios (HRs) for ASD and childhood autism were 2.9 (95% CI, 1.7-4.9) and 5.2 (95% CI, 2.7-10.0), respectively. These findings were consistent even after adjusting for maternal epilepsy and other confounders. The study concludes that maternal use of valproate during pregnancy is associated with a significantly increased risk of ASD and childhood autism, highlighting the need for caution in its use among women of childbearing potential.