1. Department of Scientific Research Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, Gansu Provincial, China
2. Laboratory Medicine Center, Lanzhou University Second Hospital, Lanzhou, Gansu Provincial, China
3. Department of Neonatology, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, Gansu Provincial, China
4. Department of Gynecology, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, Gansu Provincial, China