1. Department of Obstetrics and Gynecology, The Third Hospital of Nanchang City, Nanchang, Jiangxi, China
2. Department of Obstetrics and Gynecology, Shangrao Municipal Hospital, Shangrao, Jiangxi, China
3. Department of Obstetrics and Gynecology, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China