1. Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR China;
2. Institute of Ultrasound Imaging, Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR China;
3. Department of Pharmacy, The First Affiliated Hospital of Chongqing Medical University, Chongqing, PR China