1. Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
2. Pathology department, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
3. Department of Obstetrics and Gynecology, The Eight Affiliated Hospital of Sun Yat-sen University, Shenzhen, China