1. Department of Gynecology and Obstetrics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
2. Department of Hematology, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510630, P.R. China
3. Department of Medical Ultrasound, Institute of Diagnostic and Interventional Ultrasound, The First Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China
4. Department of Clinical Medicine, Medical College of Jinan University, Guangzhou, Guangdong 510630, P.R. China