1. Department of Gynaecology and Obstetrics, Children's Hospital of Shanxi and Women Health Center of Shanxi, Taiyuan, China
2. Department of Gynaecology, Hwaseo Maternity and Children's Hospital of Sichuan University, Chengdu, China
3. Department of Pathology, Children's Hospital of Shanxi and Women Health Center of Shanxi, Taiyuan, China