[1] West China Second Hosp, Key Lab Obstet & Gynecol & Pediat Dis & Birth Def, Dept Gynecol & Obstet, Minist Educ, Chengdu, Peoples R China
[2] Sichuan Univ, West China Hosp, State Key Lab Biotherapy, Chengdu 610064, Peoples R China
[3] Thomas Jefferson Univ Hosp, Dept Emergency Med, Philadelphia, PA 19107 USA
[4] Kaiser Permanente Santa Clara Med Ctr, Dept Surg, Emergency Med, Santa Clara, CA USA
[5] Sichuan Univ, Coll Biol Sci, Chengdu 610064, Peoples R China
[6] Sichuan Univ, West China Hosp, Dept Orthoped, Chengdu 610064, Peoples R China