Comparison of the outcomes of in vitro fertilization and embryo transfer among ethnic Chinese Yi and Han women: a multicenter retrospective cohort study 1Department of Clinical Pharmacy, Sichuan Provincial Women’s and Children’s Hospital, The Affiliated Women’s and Children’s Hospital of Chengdu Medical College, Chengdu, China 2Reproductive & Women-Children Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, China 3Sichuan Jinxin Xinan Women and Children’s Hospital,...