1. Department of Obstetrics and Gynecology; West China Second University Hospital; Sichuan University; Chengdu China
2. Department of Forensic DNA laboratory; Public security bureau of Beijing' Haidian; Beijing China
3. Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine; West China Institute of Women and Children's Health; West China Second University Hospital; Sichuan University; Chengdu China