Embryo transfer: techniques and variables affecting success

Objective: To review the literature on the variables affecting embryo transfer success or failure and to define technical factors associated with optimal outcome. Design: Literature review. Results: Avoidance of blood, mucus, bacterial contamination, excessive uterine contractions, and trauma to the endometrium is associated with optimal pregnancy and implantation rates after transcervical embryo transfer. A trial transfer, ultrasonographic guidance, and use of "soft" catheters appear to facilitate successful embryo transfer. Conclusion: An understanding of the variables associated with embryo transfer success together with adherence to techniques shown to facilitate atraumatic embryo transfer will enhance the efficiency of IVF by maximizing embryo implantation. (C) 2001 by American Society for Reproductive Medicine.