Institution: | 1. Department of Gynaecology and Obstetrics, The Second People's Hospital of Jingmen, Jingmen, Hubei, China;2. Department of Gynaecology and Obstetrics, Huai'an Second People's Hospital and The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, China;3. Department of Obstetrics and Gynecology, People's Hospital of Xuyi, Jiangsu, China |