1 Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Jinsui Road 9, Zhujiang New Town, Guangzhou 510623, China.
2 Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Jinsui Road 9, Zhujiang New Town, Guangzhou 510623, China. Electronic address: lidongzhi2013@aliyun.com.