1. Huadu District Maternal and Neonatal Healthcare Hospital of Guangzhou, Hu Zhong Hospital, Guangzhou, Guangdong, China;
2. Department of Ultrasound, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China;
3. Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China