Mingli Rao1, Xianlun Pang2, Jian Yang3. 1. Department of Obstetrics and Gynecology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China. 2. Health Management Center, The Affiliated Hospital (TCM) of Southwest Medical University, Luzhou, China. 3. Department of Orthopedic Surgery, Yongchuan Hospital of Chongqing Medical University, Chongqing, China - 15465950@qq.com.