1. Center for Reproductive Medicine, Department of Obstetrics, Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College, Hangzhou, Zhejiang, China
2. Department of Medical Record Statistics, Zhongshan Hospital of Zhejiang Province, Hangzhou, Zhejiang, China
3. Department of Ultrasound Imaging Medicine, Jinzhou Medical University, Jinzhou, Jilin, China
4. Department of Gynecology and Obstetrics, Nanxun District People’s Hospital, Huzhou, Zhejiang, China