Department of Obstetrics and Gynecology;
The First People's Hospital of Yichang;
Yichang 443000;
China;
Department of Ultrasound;
The First People's Hospital of Yichang;
Yichang 443000;
China;
Department of Obstetrics and Gynecology;
The 6th People's Hospital of Shanghai Jiaotong University;
Shanghai 200233;
China;
School of Life Science;
Xiamen University;
Xiamen 361005;
China;