FertilityEmbryo transfer: factors involved in optimizing the successSallam, Hassan NAuthor Information Department of Obstetrics and Gynaecology, University of Alexandria and Alexandria Fertility Center, Alexandria, Egypt Correspondence to Hassan N. Sallam, MD, FRCOG, PhD (London), 22 Victor Emanuel Square, Smouha, Alexandria, Egypt 21615 Tel: +20 3 424 5750 and +20 3 427 9609; fax: +20 3 487 3663; e-mail: [email protected] Current Opinion in Obstetrics and Gynecology: June 2005 - Volume 17 - Issue 3 - p 289-298 doi: 10.1097/01.gco.0000169107.08000.dd Buy Metrics Abstract Purpose of review Embryo transfer is arguably the most critical step in assisted reproduction. The purpose of this article is to review the different aspects of the procedure in the light of recent evidence. Recent findings Randomized trials have shown that significantly higher pregnancy rates are obtained when embryo transfer is performed under ultrasound guidance, the embryos are deposited in the middle part of the uterine cavity, an atraumatic technique is used and when low-dose aspirin is routinely administered following the procedure. Blood in the catheter and leaving the embryos inside it for more than 120 s diminish the pregnancy rate significantly. Air in the catheter, immediate removal of the catheter, performing two transfers in the same cycle, prolonged bed rest, sexual intercourse after embryo transfer or the use of sildenafil do not affect the results. Based on currently available evidence, Cochrane reviews have concluded that the live birth rate is not increased by delaying embryo transfer from day two to three or to the blastocyst stage, and that single embryo transfer leads to lower live birth rates than the transfer of two embryos. The value of a mock transfer a few days before the actual procedure has been challenged as the position of the uterus may change. The effect of holding the cervix with a volsellum, routinely administering antibiotics and the superiority of one catheter over the others is still to be determined. Summary Recent studies confirm the importance of the various aspects of embryo transfer. More randomized studies are needed to further evaluate them. © 2005 Lippincott Williams & Wilkins, Inc.