1. Department of Gynecology and Obstetrics, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310000, P.R. China
2. Department of Gynecology and Obstetrics, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310000, P.R. China
3. PCR Laboratory, Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310000, P.R. China
4. Department of Gynecology, Zhejiang Maternal and Child Health and Reproductive Health Center, Hangzhou, Zhejiang 310000, P.R. China