CJCP     2015 17 (1):  63-67    ISSN: 1008-8830  CN: 43-1301/R Clinical outcomes of twin pregnancies conceived by in vitro fertilization compared with spontaneous twin pregnancies ZHANG Hui-Qin, FAN Rui, TIAN Guo-Hua, LI Ling, ZHANG Zhi-Hong, ZHANG Yue-Ping Department of Pediatrics, Xijing Hospital of Fourth Military Medical University, Xi'an 710032, China Received: 2014-07-04  Revised: 2014-09-11  Online: null Supporting info