1. Department of Obstetrics/Gynecology, Stanford University School of Medicine, Stanford, California.
2. Department of Obstetrics/Gynecology, Beijing University Third Hospital, Beijing, The People's Republic of China.
3. Guangzhou Medical University, Guangzhou, The People's Republic of China.
4. Southern Medical University, OB&GYN, Guangzhou, The People's Republic of China.
5. Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California.