[1] YanCheng 1th People Hosp, Dept Obstet & Gynecol, Yancheng City 224000, Jiangsu, Peoples R China
[2] YanCheng 1th People Hosp, Dept Sci Educ, Yancheng City 224000, Jiangsu, Peoples R China
[3] YanCheng 1th People Hosp, Dept Facil, Yancheng City 224000, Jiangsu, Peoples R China
[4] Soochow Univ, Dept Obstet & Gynecol, Affiliated Hosp 1, Suzhou 215006, Peoples R China