1. Department of Internal Medicine, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, P.R. China
2. BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
3. Prenatal Diagnosis Center, Department of Obstetrics, Fuyang People's Hospital, Fuyang, Anhui 236000, P.R. China
4. Changsha Hospital for Maternal and Child Health Care, Changsha, Hunan 410007, P.R. China
5. Department of Obstetrics and Gynecology, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat‑Sen University, Jiangmen, Guangdong 529030, P.R. China