In Belgium, labour epidural analgesia (LEA) has been used for decades in the vast majority of vaginal deliveries (up to 83% of deliveries). Labour epidural analgesia is the most effective and safest way to allow pregnant women a nearly pain-free labour- and birth experience. Recent data showed that the use of LEA was associated with a reduced risk for severe maternal morbidity, neonatal resuscitation and with a reduced risk for low Apgar scores. However, prenatal exposure to labour epidural analgesia has been associated by several study groups with an increased risk for autism spectrum disorder (ASD) in the children, but these studies suffer from several important limitations which may have induced significant bias (e.g., not correcting for unmeasured confounders). Associations with other neurodevelopmental disorders (e.g., Attention Deficit Hyperactivity Disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD)) and cognitive functioning have not been investigated yet. There is hence an urgent need for a study allowing definitive conclusions by overcoming the limitations of the previous studies. The investigators will perform the first sibling-matched clinical cohort study using a prospective investigator-assessment of multiple domains of cognitive functions. The investigators hypothesize that prenatal exposure to LEA will neither be associated with reduced intelligence nor with more neurodevelopmental disorders. Validating this hypothesis holds the potential to grant women the assurance to confidently receive the most efficacious method for labour analgesia, free from apprehension that it might have adverse implications for their children's neurodevelopment.