1. Department of Obstetrics and Gynecology, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China.
2. Center of Reproductive Medicine, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
3. Reproductive Medicine Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
4. Department of Obstetrics and Gynecology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, China.
5. Department of Gynecology, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.