1. Department of Obstetrics and Gynecology, Dongguan People's Hospital (Affiliated Dongguan Hospital, South Medical University), Dongguan, China.
2. Department of Gynecology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
3. Department of Gynecology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
4. Center for Reproductive Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
5. Department of Obstetrics and Gynecology, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China.