Ok, you have gone through an entire IVF cycle. If there happens to be a surplus of embryos following fresh transfer, then embryos of sufficient quality may be considered for embryo freezing or cryopreservation.
When a couple chooses to freeze (cryopreserve) their embryos it means they will have them frozen for future use. The embryo is frozen to extremely cold temperatures, using liquid nitrogen. In this procedure of freezing virtually all biological processes cease. Under these specialized conditions the embryos can remain dormant until such time when pregnancy is desired.
Some advantages of embryo cryopreservation may include:
You will be maximizing the potential of conception with one IVF egg retrieval. In young patients (who will have a higher chance of having extra embryos available for freezing), the live birth rate with a fresh embryo transfer is around 50%. If you then add the pregnancies from using the cryopreserved embryos, the cumulative pregnancy rate will be much higher.
In Illinois, there is the Family Building Act of 1991 (details on another blog by Victoria Mostov) which mandates insurance coverage for up to four IVF cycles. An IVF cycle includes egg retrievals only. A cryopreserved embryo transfer, however, is NOT counted as a cycle. So you get additional attempts at pregnancy with the cryopreserved embryos without using up another one of your four insurance covered IVF cycles.
The pregnancy rate with cryopreserved embryos varies with patient age. In young patients, the success rate approximates 40%. This is not bad, but not as good as a fresh embryo transfer. A possible explanation for this drop is that the "best" embryos are usually used for the fresh embryo transfer.
The freezing of embryos, prevents wastage of viable normal spare embryos, which can be used at a later date.
Freezing all embryos for subsequent transfer may be advised for women who are at a high risk for developing severe ovarian hyperstimulation syndrome. By postponing pregnancy, the hyperstimulation is less severe and lasts for a shorter duration.
If embryo implantation becomes compromised in cases such as endometrial polyps, poor endometrial development or break thru bleeding at the time of embryo transfer, freezing is always an option.
When a patient is diagnosed with cancer, before they go through chemotherapy or radiation cryopreserving embryos for future use is a great opportunity to have future children.
Embryo freezing provides women the option to delay pregnancy without the risk of further damage to the egg. Advanced maternal age can cause the ovaries to age and deteriorate with time. Cryopreservation of embryos enables a couple to utilize young healthy eggs, fertilize them and keep them preserved until they are ready for a child.
Elective single embryo transfer (eSET) is an excellent option for couples who would like to minimize the risk for multiple pregnancy. Cryopreservation of your extra embryos gives you the option of preventing multiple pregnancy and at the same time maximizingf the chance of pregnancy with one retrieval. You can pursue a fresh eSET and if needed, pursue additional attempts at pregnancy, once again using your cryo-preserved embryos one at a time.
A cryo-preserved embryo transfer cycle is easy with hardly any (or no) injections depending on the protocol used. It is a lot easier as there is no stimulation or egg retrieval. All this results in a much lower cost compared to a fresh IVF cycle.
Dr. Karande is Board Certified in the specialty of Obstetrics and Gynecology as well as the subspecialty of Reproductive Endocrinology and Infertility. He is a Fellow of the American College of Obstetricians and Gynecologists and Member of the American Society for Reproductive Medicine.