Pereira N, et al. - A retrospective cohort study is carried out to examine the relationship between ABO blood type and live-birth outcomes in patients undergoing in vitro fertilization (IVF) with day 5 single embryo transfer (SET). The outcome of this study proposes that ABO blood type is not related to live-birth rate, birth weight, or gestational age at delivery in patients undergoing IVF with day 5 SET.