Embryo transfer is a key step in the in vitro fertilization (IVF) process. It involves placing an embryo into the uterine cavity after optimal endometrial preparation, creating the best possible conditions for implantation and maximizing the chances of pregnancy.
The embryo transferred can either be a “fresh” embryo, meaning it originates from oocytes fertilized 4 to 6 days earlier following ovarian puncture, or a vitrified embryo. In the latter case, the embryo was frozen during a previous IVF attempt and will be carefully thawed a few hours before transfer.
The procedure takes place within the assisted reproduction center, in a dedicated room adjacent to the laboratory. This setup minimizes temperature variations, ensuring that the embryo remains at optimal conditions—from the moment it is removed from the incubator (37°C) to its transfer into the uterine cavity. All equipment used during the procedure is sterile and single-use.
Once the patient is comfortably positioned on the examination table, the gynecologist carefully exposes the cervix using a speculum and gently removes cervico-vaginal secretions with a sterile gauze soaked in saline solution. The embryo(s), suspended in a small drop of culture medium, are loaded into a flexible catheter connected to a syringe containing approximately 3 mm of air.
The catheter is then delicately inserted through the cervical canal into the uterine cavity. The procedure is typically performed under ultrasound guidance, allowing the gynecologist to precisely position the catheter tip in the upper third of the uterine cavity, the optimal site for implantation. Once correctly positioned, the gynecologist gently presses the syringe plunger, releasing the embryo(s) into the uterus.
Finally, the catheter is carefully handed back to the embryologist, who meticulously checks that no embryo remains within its walls, ensuring a complete and successful transfer.
The embryo transfer is now complete. While a short rest period is often suggested, it is not medically necessary. Several studies have demonstrated that resting after the procedure does not improve pregnancy rates. Resuming normal daily activities—while avoiding excessive physical exertion—is completely safe and even recommended to maintain overall well-being.
