1. Department of Gynaecology, Huangdao District Chinese Medicine Hospital, Qingdao, Shandong, China
2. Department of Obstetrics, Huangdao District Hospital of Traditional Chinese Medicine, Qingdao, Shandong, China
3. Department of Gynaecology, Qingdao Hospital of Traditional Chinese Medicine, Qingdao, Shandong, China