Department of Hematology, First Affiliated Hospital of Hebei North University, 075000 Zhangjiakou, Heibei, China;
Department of physiology, Basic Medical College, Hebei North University, 075000 Zhangjiakou, Heibei, China;
Department of Obstetrics and Gynecology, the Sixth Hospital of Zhangjiakou, 075000 Zhangjiakou, Heibei, China;