IVF with Frozen Eggs
Women undergoing in vitro fertilization (IVF) may be interested in using frozen donor eggs during the IVF process. Frozen donor eggs with IVF may be desirable for a number of reasons, especially if you are having trouble getting pregnant.
Starting the process
If you are interested in an IVF cycle with frozen donor eggs, make an appointment with a reproductive endocrinologist (RE). During your first visit, you will complete a thorough infertility evaluation. Remember that 20 percent of all patients will have more than one cause of infertility. Accordingly, a thorough evaluation needs to be performed.
Choosing a donor
After your infertility evaluation is complete, you will access a database of available egg donors. You will choose a donor and then your frozen eggs will be shipped in a frozen state to an infertility center. The eggs will be safely stored at the center until ready for use.
Getting pregnant with frozen eggs
To prepare your uterus for IVF with frozen eggs, you will generally start by taking estrogen orally and also administering progesterone either vaginally or via injections. Once the uterus has appropriately matured, the eggs are then thawed and fertilized with sperm. The resultant embryos are cultured for 3 to 5 days and generally one or two embryos is transferred into your uterus.
IVF and ICSI
The frozen eggs are thawed and fertilized with sperm via a process called intracytoplasmic sperm injection (ICSI). This procedure, ICSI, is strongly recommended after egg freezing since studies have shown hardening of the zona pellucida (the outer layer of the egg) after the egg freezing process. Due to this hardening, ICSI improves oocyte fertilization rates and ultimately success rates. After fertilization, the embryos are cultured typically for 3 to 5 days. At this point the embryos are transferred in the standard IVF procedure.
Please note that, other than the hardening of the zona pellucida, there do not appear to be any significant changes in the egg structure during the egg freezing process.
Why use frozen instead of fresh?
There are several benefits of using frozen eggs during the IVF process. We list some of those benefits here:
- One of the differences between a transfer using frozen eggs or fresh eggs is that the frozen eggs are immediately available. The timeline to have the eggs ready for use is two to three months shorter than if you were using fresh eggs during IVF.
- The use of frozen eggs also gives couples an increased selection of donors as eggs can now be used from centers throughout the country, also offering couples a wider selection of eggs.
- Egg freezing in the donor egg treatment cycles results in quicker, more reliable cycles.
Egg freezing also allows for eggs to be quarantined for sexually transmitted disease (STD) testing prior to their use. Current fresh donor egg cycles involve the testing of the donor for sexual transmitted diseases immediately before the donation cycle. However, the eggs are not quarantined and held for a period of time before the donation - as is currently done in sperm donation. To date there have not been published cases of STDs from fresh egg donation although the quarantining of frozen eggs should help to further lower that risk.
Risks do exist
Is it safe to freeze eggs? So far the early research suggests yes, however, more research is needed. A rapid freezing process called vitrification is making it possible for donors to harvest their eggs and freeze them, unfertilized. And the advantages of the process are enormous. Once frozen, it appears unfertilized eggs will be viable for up to 20 or 30 years.
Frozen eggs do help many couples get pregnant. However, the use of frozen eggs with IVF is a new technology and therefore conveys some unknown risks. A downside to egg freezing is a slightly lower pregnancy rate when using embryos resulting from frozen eggs. This pregnancy rate may actually improve with time as the egg freezing and thawing technology gets refined.
You might wonder: “Does egg freezing increase the risk of chromosomal abnormalities or birth defects in children born from IVF with frozen eggs?” So far, studies on egg freezing are very reassuring, as there does not appear to be any increased risk of birth defect or chromosomal abnormalities from the egg freezing process. After the successful thaw of frozen eggs, fertilization has shown similar rates of chromosomal abnormalities between embryos from fresh eggs versus embryos from frozen eggs. However, further studies are necessary.
Frozen egg IVF success rates
At the present time there appears to be a slight decrease in pregnancy rates from the use of frozen eggs compared with fresh eggs. The pregnancy rate ultimately depends on the quality of the eggs that are frozen, which is directly related to a patient's age and the underlying diagnosis. There is significant variability with the pregnancy rates depending on several important factors, including:
- The freezing technique being used by the center
- The experience of the fertility center
- The quality of the eggs
- The quality of the sperm
It is important to note that a woman's uterus generally does not age significantly with time. Pregnancy rates with the use of frozen eggs ultimately depend on the age at which the eggs were frozen and the egg quality at the time of freezing. To truly understand what your pregnancy rate would be with frozen eggs, I would strongly recommend a consultation with your RE.
The cost of IVF with frozen eggs
The cost of egg freezing will vary significantly from center to center. Essentially the egg freezing process breaks an IVF cycle into two parts, separating the stimulation and egg retrieval from the embryo transfer. Therefore overall costs per cycle, including egg retrieval and transfer, are likely to be similar.