Egg Freezing

What Is Egg Freezing?

Egg freezing, also called oocyte cryopreservation, is a rapidly advancing technology involving: stimulating, extracting, freezing, and storing of a woman’s eggs (oocytes). The eggs can be thawed months or even years later. Then, they maybe thawed, and fertilized after exposure to sperm generating embryos. These embryos then can be transferred to the uterus in an attempt to achieved a successful pregnancy. Egg freezing offers women the potential to take control of their reproductive health until they are ready to attempt pregnancy.

Cryopreservation is not new in human reproduction. Human sperm has been frozen and stored since the 1950s and human embryos cryopreserved since the 1980s. Both sperm and embryo freezing are routine procedures performed successfully in most Fertility Centers around the world. Egg freezing, however, is not yet routine. Issues in freezing and thawing of human eggs center on the high water content of the egg itself. Using conventional freezing methods, the egg is susceptible to both damage and destruction as ice crystals within the egg can cause it to fracture upon thawing. Safety issues also raised concerning the generation of chromosomal abnormalities within the thawed egg. These concerns stem from studies performed in mice over 20 year in which higher incidences of chromosome abnormalities were observed in previously frozen mouse eggs. Due to these concerns, egg freezing was labeled as experimental.

The advent of a new cryopreservation technology called vitrification has revolutionized our ability to thaw successfully frozen eggs. In vitrification, rapid cooling rates spare the egg from forming ice crystals within; and as a result, they are less likely to fracture upon thawing.

Having the tools to predictably and safely thaw eggs, the stumbling blocks once presented are no more. Current pregnancy success rates following thawing are beginning to rival those achieved when fresh (not frozen) eggs are used. Over 1000 babies have been born world wide following egg freezing with rates of birth defects and chromosome abnormalities no different than observed in the general population. These results have compelled many to advocate the removal of the experimental status of this innovative procedure.

Who Should Consider Egg Freezing?

Egg freezing has the potential to be of benefit to anyone desiring to preserve their fertility. There are multiple groups of people for whom egg freezing may be beneficial including:

1. Women diagnosed with cancer who have not as yet begun chemotherapy or radiation treatments. Often these aggressive and necessary medical regimens can render women incapable of conceiving with their own eggs.
2. Women who have been advised to have surgery to remove their ovaries due to severe endometriosis or other diseases that damage or destroy their ovarian function;
3. Women with rheumatologic disorders or multiple sclerosis who must be on medications that may destroy ovarian function;
4. Women having in vitro fertilization who are concerned with banking of embryos or where embryo freezing is not an option for ethical, religious or moral reason.
5. Women who wish to donate their eggs for others as part of a donor egg bank which would allow responsible quarantine of donated eggs not currently available with fresh human egg donation;
6. Women with a family history of premature menopause and others in danger of losing ovarian function earlier than would normally be expected;
7. Women who desire to delay becoming pregnant due to career choices, continuing education, not having a partner, or for other personal or medical reasons because freezing healthy eggs at an early age may optimize chances for future fertility.

Who Is A Candidate For Egg Freezing?

Candidates for entry into our egg freezing program are evaluated at all of our office locations. A review of your medical records can be done prior to your scheduled visit to determine probable qualification for the program but does not substitute for an initial consultation which is required prior to program enrollment.

Egg freezing depends upon egg production which is based on the number of eggs that are still in your ovaries and how they will respond to the medications required for the ovaries to make eggs.

The three most important factors in determining your chances for potential success with egg freezing are:

• Your age;
• Your baseline (Cycle Day 3) level of Follicle Stimulating Hormone (FSH) and Estradiol (E2) as determined by a blood test;
• Your “resting” ovarian follicle count as determined by pelvic ultrasound.

Best Candidates (excellent chance of success)

• Age under 30 years
• FSH less than 7, E2 less than 70
• More than 10 follicles/ovary

Good Candidates (good chance of success)

• Age 31-34 years
• FSH less than 8, E2 less than 80
• More than 10 follicles /ovary

Fair Candidates (moderate chance of success)

• Age 35-37 years
• FSH less than 10, E2 less than 100
• More than 5 but less than 10 follicles/ovary

Poor Candidates (guarded chance of success)

• Age 38-39
• FSH less than 10, E2 less than 100
• More than 5 but less than 10 follicles/ovary

Worst Candidates (non-eligible due to unlikely chance of success)

• Age 40 years or above
• FSH greater than 10, E2 greater than 100
• Less than 5 follicles/ovary

What Are The Steps In The Treatment Process?

The treatment process involves the preparation of your ovaries for the production of the mature eggs needed for freezing. In order to retrieve eggs for freezing, you must undergo the same hormone-injection process as in-vitro fertilization (IVF). The only difference is that following egg retrieval, your mature eggs will be frozen. At a later designated time, a select number of eggs may be thawed, fertilized and embryos transferred to the accepting uterus. Although the clock continually ticks for egg quality and production, the uterus is virtually immune to the effects of aging.

Step One: Explanation and Consents

A full explanation detailing this process will be provided at the time of your formal entry into the egg freezing program. You will be asked to meet with your medical care team who will explain the process in detail and have you sign consent acknowledging your participation in the egg freezing program. Following informed consent all of the medicines you will need can be ordered.

Step Two: Pre-Stimulation

Once your normal menstrual period begins, you will be instructed to start medication depending upon the individualized treatment protocol that has been tailored. We will optimize your protocol optimize to generate as many mature eggs as is possible. This often starts with oral contraceptives for 21 days to maximize mature egg production in the following stimulation cycle.

Step Three: Stimulation

Ovarian stimulation involves the self administration of fertility medications designed to allow you ovaries to begin the growth of multiple healthy eggs that will be removed for subsequent freezing. These medications are given subcutaneously with a small needle and syringe. You will be shown how to take these medications prior to using them. While taking these medications, you will need to come to one of our offices first thing in the morning for monitoring. Monitoring includes painless vaginal ultrasound assessments of follicle growth and blood tests approximately 3-4 times over the 8-12 day period you are taking these medications. After your ovarian follicles have attained a sufficient size and your blood level of estrogen is adequate, you will be instructed to take an intramuscular injection, “Trigger Shot” that will prepare your eggs for retrieval.

Step Four: Egg Retrieval

You will be scheduled for egg retrieval which is performed 36 hours after taking the “Trigger Shot” and following administrating a light anesthetic, sedative, and pain medication that allows for a rapid recovery. The egg retrieval should take no more than 10 -15 minutes to accomplish. You should be able to go home when it has been determined that you are stable, usually within one hour of the procedure.

Step Five: Oocyte Freezing

Following your egg retrieval, the eggs will be prepared for freezing using a process called vitrification as mention above. The vitrification process will protect the eggs from ice crystal formation. They will be transferred to a liquid nitrogen storage chamber where they will be effectively stored in the frozen state.

Step Six: Egg Storage

The initial short term storage will occur at our facility; however, long term storage will be required at a special “cryobank” which is a facility where long term secure maintenance of frozen human specimens occurs and where they may be stored indefinitely. You will be given information this as part of your consult explaining the details of the process. The cryopreservation of your eggs is a separate procedure unrelated to the long term storage of the frozen eggs or later treatments to thaw, fertilize, and transfer embryos to you and as such separate fees are applied.

Step Seven: Thaw and Use of Your Frozen Eggs

When you decide to try and become pregnant, you will need to make arrangements with our facility at least two months in advance to go over what is required prior to thawing, fertilization and transfer of embryos. The fertilization of previously cryopreserved eggs requires intracytoplasmic sperm injection (ICSI) which avoids most of the usual barriers to fertilization by the direct injection of a single sperm into an egg. Originally this procedure was designed to specifically treat male infertility but is now used in many cases of IVF where fertilization needs to be maximized. One or two resulting embryos can be painlessly transferred under ultrasound guidance. Any remaining embryos that are deemed to be potentially viable can be frozen for later use if desired.

Will Egg Freezing Enable Me to Have a Baby?

Many factors go into making a successful pregnancy. Your chances of ultimately having a baby following egg freezing are greater when the oocytes are both younger and greater in number.

Although we do have testing parameters that will suggest the type of anticipated response, we will not know about your egg production until five to six days after you start your stimulation cycle. Unfortunately some women will produce few eggs. Follicle number does not equal mature egg number and only mature eggs are frozen. We anticipate that up to 80% of the cryopreserved eggs will survive the thawing process. Approximately 80% of these successfully thawed eggs will allow themselves to be fertilized. A select number of the fertilized egg will develop into an embryo that will create a pregnancy. However, not every pregnancy will end with a healthy baby as the miscarriage rate is approximately 15%.

There is no absolute egg number threshold for cancellation. However, if few eggs are obtained then your chances of success may be lower than if there were many eggs. Having only a few eggs collected most likely means your fertility is passing. Getting five eggs may be better than nothing, because as months pass, you may make fewer in the future. Stopping without having the egg retrieval and restarting in a short amount of time using a different stimulation protocol would probably be the best choice. However, even when making stimulation changes you may make the same or even fewer eggs next time. Ideally you should have at least 10 eggs to freeze if you under age 35 and 20 if you are age 35 year or older. Unfortunately, if may be difficult for many women over 35 years old to make this many mature eggs following only one stimulation cycle and thus multiple stimulation cycles may be necessary to acquire enough mature eggs to freeze.

Success rates per cycle are up to 35% depending primarily upon the age of the woman at the time of having her eggs frozen and other fertility factors.