Frozen embryo transfer involves replacing an embryo in the uterine cavity, after preparation of the uterine mucosa. This embryo will have been frozen by vitrification during a previous IVF or IVF ICSI attempt. It will be devitrified a few hours before transfer.
Embryo transfer is the final stage of IVF treatment, and although quick and painless, it must be carried out under the best possible conditions.
It can be a “fresh” embryo, i.e. from the oocytes fertilized between 4 and 6 days earlier after ovarian puncture, or a vitrified embryo transfer. In the latter case, the embryo will have been frozen during a previous IVF attempt and will be devitrified a few hours before transfer. Embryo transfer takes place on the premises of the MPA center, in a room adjoining the laboratory, so as to minimize temperature variations between the moment when the embryo is taken out of the incubator at 37 degrees and the moment when it is placed back in the uterine cavity. All equipment is sterile and single-use.
Once the patient is settled on the examination table, the gynecologist exposes the cervix with a speculum and wipes away cervico-vaginal secretions with a sterile compress soaked in saline solution. The embryo(s) contained in a drop of culture medium are mounted in a flexible catheter connected to a syringe filled with some 3mm of air. The tip of the catheter is inserted into the cervical canal and then into the uterine cavity. This procedure is usually performed under ultrasound control, to position the catheter tip in the upper third of the uterine cavity. Once the correct position of the catheter has been verified, the gynecologist pushes the plunger of the syringe to release the embryo(s) into the uterine cavity. The catheter is again handed over to the laboratory technician, who checks that no embryos have stuck to its wall.
Embryo transfer is then complete. It is not necessary to observe a rest period after embryo transfer, although this is generally suggested. Several studies have shown that rest does not increase the chances of pregnancy. A return to normal life without excessive exertion is entirely possible, and even recommended.
