1. Department of Gynaecology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
2. Precision Medical Center, The Third Affiliated Hospital of Harbin Medical University, Harbin, China
3. Department of Ultrasound of Obstetrics and Gynaecology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
4. The State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
5. College of Science, Harbin Engineering University, Harbin, China