1. Prenatal Diagnosis Center, Nanchang, Jiangxi 330006, P.R. China
2. Key Laboratory of Women's Reproductive Health of Jiangxi Province, Jiangxi Provincial Maternal and Child Health Hospital, Nanchang, Jiangxi 330006, P.R. China
3. Department of Clinical Medicine, Jiangxi Health Vocational College, Nanchang, Jiangxi 330052, P.R. China
4. Department of Gynecology, Jiangxi Provincial Maternal and Child Health Hospital, Nanchang, Jiangxi 330006, P.R. China
5. Department of Pathology, Jiangxi Provincial Maternal and Child Health Hospital, Nanchang, Jiangxi 330006, P.R. China
6. Key Laboratory of Women's Reproductive Health of Jiangxi Province, Jiangxi Provincial Maternal and Child Health Hospital, Nanchang, Jiangxi 330006, P.R. China