1 Departments of Obstetrics and Gynecology (H.J., Y.L., and S.Y.), and Orthopedic Trauma and Microsurgery (L.G.), First Affiliated Hospital of Sun Yat-sen University, No. 58, the 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong, China 510080. yszlfy@163.com.
2 Department of Obstetrics and Gynecology, Jiangmen Wuyi Traditional Chinese Medicine Hospital, No. 30, East Huayuan Road, Jiangmen, Guangdong, China 529000.