Association between ABO blood type and live-birth outcomes in single-embryo transfer cycles

Objective To investigate the association between ABO blood type and live-birth outcomes in patients undergoing IVF with day 5 single-embryo transfer (SET). Design Retrospective cohort study. Setting University-affiliated center. Patient(s) Normal responders, Intervention(s) None. Main Outcome Measure(s) Live-birth rate was the primary outcome. Secondary outcomes were birth weight and gestational age at delivery. Univariate and multivariable logistic regression was used to examine the association between blood type and live birth, while controlling for confounders. Odds ratios (OR) with 95% confidence intervals (CI) for live birth were estimated. Result(s) A total of 2,329 patients were included. The mean age of the study cohort was 34.6 ± 4.78 years. The distribution of blood types was as follows: A=897 (38.5%); B=397 (17.0%); AB=120 (5.2%); and, O=1,915 (39.3%) patients. There was no difference in the baseline demographics, ovarian stimulation, or embryo quality parameters between the blood types. The unadjusted ORs for live birth when comparing blood type A (referent) with blood types B, AB, and O were 0.96 (95% CI, 0.6–1.7), 0.72 (95% CI, 0.4–1.2), and 0.96 (95% CI. 0.6–1.7), respectively. The adjusted ORs for live birth remained not significant when comparing blood type A to blood types B, AB, and O individually. No difference in birth weight or gestational age at delivery was noted among the four blood types. Conclusion(s) Our findings suggest that ABO blood type is not associated with live-birth rate, birth weight, or gestational age at delivery in patients undergoing IVF with day 5 SET.