1. F Xie, Obstetrics and Gynecology, First Affiliated Hospital of Anhui Medical University, Hefei, China
2. J Zhang, Obstetrics and Gynecology, First Affiliated Hospital of Anhui Medical University, Hefei, China
3. M Zhai, First Clinical Medical College, Anhui Medical University, Hefei, China
4. Y Liu, Obstetrics and Gynecology, First Affiliated Hospital of Anhui Medical University, Hefei, China
5. H Hu, First Clinical Medical College, Anhui Medical University, Hefei, China
6. Z Yu, Obstetrics and Gynecology, First Affiliated Hospital of Anhui Medical University, Hefei, China
7. S Lin, Histology and Embryology, Anhui Medical University, Hefei, China
8. D Liang, Obstetrics and Gynecology, First Affiliated Hospital of Anhui Medical University, Hefei, China
9. Y Cao, Obstetrics and Gynecology, First Affiliated Hospital of Anhui Medical University, Hefei, China