Does the presence of blood in the catheter or the degree of difficulty of embryo transfer affect pregnancy

OBJECTIVE: To estimate the effect of blood at the time of embryo transfer and the difficulty of embryo transfer on clinical pregnancy rates. DESIGN: A retrospective cohort study of all patients who underwent ART with embryo transfer between January 2012 and December 2013. MATERIALSANDMETHODS: Generalized estimating equations (GEE) with nesting for repeated cycles were used for all analyses. Univariate modeling was performed to assess factors associated with clinical pregnancy and a final multivariate (adjusted) GEE model accounted for all significant confounders. Physicians subjectively graded embryo transfers as easy, medium, or hard at the time of transfer. The primary outcomewas ongoing pregnancy. RESULTS: 784 patients undergoing 941 embryo transfer cycles were included. The presence of microscopic blood at embryo transfer was associated with more difficult embryo transfers, retained embryos, and presence of mucous in the catheter. In the univariate analysis, embryo transfer with blood was not associated with ongoing pregnancy (P1⁄40.11), while the degree of difficulty for embryo transfer was strongly negatively associated. In the final multivariate GEEmodel, the only factors associated with ongoing pregnancy included the degree of difficulty of the embryo transfer, female age, and blastocyst transfer.