1 Department of Obstetrics and Gynecology, The 3rd Affiliated Hospital of Shenzhen University, Luohu People's Hospital, Shenzhen, Guangdong, China (all authors).. Electronic address: vinsonpan@126.com.
2 Department of Obstetrics and Gynecology, The 3rd Affiliated Hospital of Shenzhen University, Luohu People's Hospital, Shenzhen, Guangdong, China (all authors).