Epidemiological studies found that about 10% of children in the world suffer from neurodevelopmental disorders, such as Autism Spectrum Disorder (ASD), Intellectual Disability, Attention-Deficit Hyperactivity Disorder (ADHD) and others. Excessive weight gain during pregnancy appears to be an important factor affecting the health of pregnant women and their offspring. Weight gain during pregnancy changes with gestational age, and the total weight gain during pregnancy may not be able to accurately assess and identify the adverse maternal and infant outcomes. Therefore, it is of great significance to explore the weight changes at different time points during pregnancy. Further, the mechanism mediating the association between weight gain during pregnancy and childrens' neurodevelopmental disorders is still unclear. Epigenetic mechanisms may play an important role. This study will test the hypothesis that excessive weight gain during pregnancy may cause fetal epigenetic changes, affect the growth pattern of offspring, affect the brain development of children, and increase the risk for neurodevelopmental disorders in children.