1. Obstetrical Department VIII, The Fourth Hospital of Shijiazhuang (The Obstetrics and Gynecology Hospital of Hebei Medical University), Shijiazhuang, Hebei 050000, China
2. Prenatal Diagnosis Center, The Fourth Hospital of Shijiazhuang (The Obstetrics and Gynecology Hospital of Hebei Medical University), Shijiazhuang, Hebei 050000, China
3. Health Care Center, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China