Air in the transfer catheter does not affect the success of embryo transfer

Objective: To investigate the effect on embryo transfer (ET) success of air loaded into the transfer catheter to bracket the embryo-containing medium. Design: Prospective, randomized study. Setting: University teaching hospital. Patient(s): One hundred two consecutive patients undergoing ET after IVF. Intervention(s): In group 1 (n = 52), embryos were loaded as follows: 200 muL of air in the syringe, 100-125 muL of air in the proximal part of the catheter, 20-25 muL of medium containing the embryos to be transferred, and 10 muL of air at the tip of the catheter. In group 2 (n = 50), the syringe and the entire catheter were filled with medium and the embryo-containing medium (20-25 muL) was aspirated without being bracketed by air spaces. Main Outcome Measure(s): Implantation and pregnancy rates. Result(s): No differences were found between groups rates. 1 and 2 with respect to implantation and pregnancy Conclusion(s): The air loaded into the transfer catheter to bracket the embryo-containing medium has no negative effect on ET success.