Li-Lin Yang1, Ying Zhou2, Song-Ping Luo3. 1. First School of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China. 2. Department of Obstetrics and Gynecology, First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China. 3. First School of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China. Electronic address: gynspluo@hotmail.com.