A frozen embryo transfer (FET) cycle is a month in which the woman’s uterus is prepared with hormones and a reasonable number of embryos (usually one or two) are thawed and transferred. Success rates for a frozen/thawed embryo transfer have now surpassed that of a fresh embryo transfer (ET) especially if the embryo(s) was/were flash-frozen (vitrified). Vitrification is a fast-freezing method that has a very high success rate, ensuring that over 90% of embryos will survive the process. The embryos are first dehydrated and then flash frozen and stored in liquid nitrogen tanks.
The embryologist loads the embryo(s) into a soft catheter and the physician guides the catheter past the cervix to a depth previously determined. A nurse will monitor this process using the abdominal sonogram to help guide the physician. About 10 days after the ET we will test the patient for pregnancy with a blood test.
Cryopreservation refers to the cooling of cells and tissues to sub-zero temperatures in order to stop all biologic activity and preserve them for future use. This process can be used for a woman’s eggs to preserve them for future child-bearing. By utilizing the most advanced freezing technology available (vitrification or flash-freezing), we are now able to achieve egg survival rates of about 90%.
The process of egg freezing is identical to going through an IVF cycle with the exception of fertilization (combining the egg and sperm together to form an embryo). In the case of egg freezing, no sperm are required. As with most aspects of fertility treatment, success rates are based on the age of the woman. The younger a woman is when she freezes her eggs, the more chance she has for a successful pregnancy. In general, we recommend the collection of 9-10 eggs for every desired pregnancy.
The most common reasons a woman chooses to freeze her eggs include: