Many clinics today are advising patients to undergo what is called a “freeze-all” IVF cycle rather than transferring a fresh embryo after retrieval and fertilization. This is because several IVF centers have recently suggested that freezing all embryos immediately, rather than transferring them during a stimulated cycle, may improve IVF outcomes. Some programs even report higher pregnancy and birth rates in cycles where there is a break between the retrieval and the transfer.
Wondering what a freeze-all cycle is and if you should ask your doctor about it? Let’s discuss!
A freeze-all cycle is like the in vitro fertilization (IVF) process, but all of the embryos are immediately frozen for future transfer into the woman’s uterus. The embryos are frozen using vitrification, which instantly freezes your embryos. Prior to the use of vitrification, a slow freeze process was used and often compromised the quality of the egg and/or embryo both when it was freezing and later on, when it was being thawed. Today, the fast freeze technology keeps the integrity of the eggs and/or embryos with minimal impact.
There are several reasons why freeze-all cycles might be worth asking your doctor about.
First, some doctors wonder about the uterine lining directly after going through a stimulated retrieval. Medications such as hormone injections like Follistim, Gonal-F, etc. are used to help produce the eggs to retrieve and subsequently fertilize, but they also may accelerate the development of the uterine lining to be ahead of the developmental stage of the embryo. This could potentially impact the chances of the implantation (meaning the embryo implanting in the uterus, creating a pregnancy). Some believe that if you wait until the woman’s body is back to her “normal” state, it will increase chances of implantation.
Second, if you freeze your embryos before transferring them, you have the option of testing them either through something called Pre-implantation Genetic Diagnosis (PGD) or Pre-implantation Genetic Screening. Patients may choose to have embryo testing to confirm that the embryo has a normal number of chromosomes (translation: are genetically healthy), or see if their embryos contain a certain genetic mutation that can result in disease.
The embryos are frozen after the biopsy and are later transferred once the results are available for confirming the health of the embryo being transferred. This can increase the likelihood of successful implantation and decrease the chance of miscarriage.
Everyone is different, though, and every doctor’s treatment protocol can vary depending on your family, as well as fertility history, or any diagnosis you may have. If you are interested in learning more about freeze-all cycles, definitely speak to your doctor so you and your RE can decide what’s the best route for you.