The SLCDS aims to identify the environmental predictors of women’s physical and mental health in pregnancy and the first year postpartum, and investigate whether the mother’s perinatal illness increased the children’s risk for cognitive, emotional, and behavioural problems. In 1986, around 250 pregnant women were recruited from two antenatal clinics in South London, England, United Kingdom, and participated in a baseline assessment between 14 and 20 weeks of pregnancy. A subset of almost 180 women were assessed again during pregnancy at 36 weeks, and twice during the first year postpartum, at 3 and 12 months. Children's birth measurements were collected. Parents and their children were followed up at 4, 11, 16, and 25 years.