1. Department of Qingdao Medical College, Qingdao University, Qingdao, Shandong, China
2. Department of Intensive Care Unit, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
3. Department of Reproductive Medicine, The Affiliated Women and Children’s Hospital of Qingdao University, Qingdao, Shandong, China