1. Prenatal Diagnosis Center, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People’s Hospital), Dongguan, People’s Republic of China
2. Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou, People’s Republic of China
3. Clinical Laboratory, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People’s Hospital), Dongguan, People’s Republic of China
4. Department of Obstetrics and Gynecology, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People’s Hospital), Dongguan, People’s Republic of China