1 Department of Obstetrics, Baoan Maternal and Child Health Hospital, Jinan University, Shenzhen, China.
2 Department of Joint Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Clinic for Gynecology, Charite-Universitatsmedizin Berlin, Corporate Member of Freie Universit Berlin, Humboldt-Universit zu Berlin, and Berlin Institute of Health, Berlin, Germany.
3 Department of Obstetrics, Baoan Maternal and Child Health Hospital, Jinan University, Shenzhen, China. Electronic address: zhuyuanfang111@163.com.
4 Department of Obstetrics, Baoan Maternal and Child Health Hospital, Jinan University, Shenzhen, China. Electronic address: guofang2200@163.com.