1. Department of Emergency, Zhangqiu District People's Hospital, Jinan, Shandong 250200, P.R. China
2. Department of Obstetrics, Zhangqiu District People's Hospital, Jinan, Shandong 250200, P.R. China
3. Department of Nephrology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China