1. Perinatal Center The Fourth Hospital of Shijiazhuang Shijiazhuang China
2. Department of Neurosurgery The Second Hospital of Hebei Medical University Shijiazhuang China
3. Prenatal Diagnostic The Fourth Hospital of Shijiazhuang Shijiazhuang China
4. Department of Obstetrics The Fourth Hospital of Shijiazhuang Shijiazhuang China
5. Department of Obstetrics Gaocheng District Hospital of Traditional Chinese and Western Medicine Shijiazhuang China
6. Department of Biology Hengshui University Hengshui China