1. Reproductive Medicine Center, Affiliated Shenzhen Maternity & Child Healthcare Hospital, Southern Medical University, Shenzhen Maternity and Child Medical Science Institute, Shenzhen 518042, P. R. China
2. Department of Pathology, Affiliated Shenzhen Maternity & Child Healthcare Hospital, Southern Medical University, Shenzhen Maternity and Child Medical Science Institute, Shenzhen 518042, P. R. China