Yuanyuan Gu1, Tong Ru1, Yi-Hua Zhou2, Yali Hu3. 1. Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Jiangsu, China. 2. Departments of Experimental Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Nanjing University Medical School, Jiangsu, China; Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Jiangsu, China. 3. Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Jiangsu, China; Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Jiangsu, China. Electronic address: dtylhu@126.com.