1. Breast Center, Qingdao Central Hospital, Qingdao, Shandong 266033, P.R. China
2. Department of Cardiology, Qingdao Central Hospital, Qingdao, Shandong 266033, P.R. China
3. Department of Obstetrics, Qingdao Central Hospital, Qingdao, Shandong 266033, P.R. China