FACT 4 Child is a follow up study of mothers who participated in the Folic Acid Clinical Trial (NCT01355159) and their children at 4-6 years of age to determine the effect of high dose folic acid supplementation on social impairments associated with Autism Spectrum Disorders (ASDs), and deficiencies in a range of executive function and emotional and behavioural problems in young children, and the risk of death.