Background: Early marriage and fertility are major social determinants of health and wellbeing. Rapid shifts in the past three decades, including a rise in sexual activity in unmarried adolescents, a large population of young migrant workers, and a high proportion of males relative to females, have the potential to alter patterns of reproductive health in Chinese adolescents and young women. We aimed to establish long-term trends of marriage and fertility for girls and women aged 15–24 years in China.
