Delayed childbearing is a social phenomenon in which women are delaying having children. This trend can be observed in both developed and developing nations. The reasons for delayed childbearing vary greatly, including the development of contraceptive use, improvement in women's educational levels and employment, and changes in family policies. Delayed childbearing also has a series of macro and micro consequences, such as lower fertility rate, higher risk of congenital defect, and a greater generation gap between parents and children.