Egg Freezing (Oocyte Cryopreservation)

• Overview: Egg freezing is the process of retrieving eggs from the ovaries, then freezing and storing them (cryopreservation) for conception in the future.
• Why freeze eggs: Egg freezing can be used to preserve fertility for personal reasons such as age or medical reasons including before undergoing specific cancer treatments.
• Process: Freezing eggs involves the in vitro fertilization (IVF) process, including the use of medication to stimulate multiple eggs to develop and egg retrieval. When the patient is ready to use the eggs, they are thawed, fertilized with partner or donor sperm in the lab, and an embryo is transferred into the woman’s uterus (womb) for implantation.
• Risks: A few risks are involved with the egg freezing process including ovarian hyperstimulation syndrome, surgical complications and emotional effects, but luckily these are rare.

What is egg freezing?

Egg freezing, also called planned oocyte cryopreservation, is a form of fertility preservation where mature eggs are retrieved from the ovaries after ovarian stimulation. The eggs, or oocytes, are then frozen and stored in a cryotank in a process called cryopreservation, until the individual decides to use the eggs for conception through fertility treatment. The thawed eggs retain the same ability to be fertilized as they had at the time of freezing.

The American Society for Reproductive Medicine (ASRM) declared that egg freezing was no longer an experimental procedure in 2012. As advances in the field of reproductive treatments take place, the Society for Assisted Reproductive Technology (SART) reports that egg freezing is continuing to grow in popularity.

One such advance is the technique used to freeze the eggs called vitrification, or rapid freezing. This new technique prevents ice crystals from forming when eggs are frozen, making the eggs less fragile and less prone to injury during thawing.

New techniques in IVF and egg thawing have also increased the success of this process. SART reports that in 2018, 13,275 patients pursued fertility preservation through egg freezing, up from 8,825 in 2016.

Dr. Belinda “Sissy” Sartor focuses on egg freezing. Learn more about her.

Why freeze your eggs to preserve fertility?

There are multiple reasons for planned oocyte cryopreservation including fertility preservation prior to medical/surgical treatment or to delay family building for career planning. Each individual situation is unique, and we would be happy to provide more information to help anyone decide if egg freezing is the right option.

Medical reasons to freeze eggs

• Medications: Some medications can diminish ovarian function and reduce a woman’s ability to conceive without fertility treatments.
• Family history: If a woman’s family history shows signs of early menopause or ovarian cancer, egg freezing may be a good precaution.
• Age: Though not a specific medical condition, advancing age causes the quantity and quality of a woman’s eggs to deteriorate. Freezing eggs at a younger age (in a person’s 20s or early 30s is best) means the eggs are more likely to be of good quality when needed for future pregnancy.
• Autoimmune disease: Autoimmune diseases, along with other health conditions, can harm fertility over time.
• Surgery: If a woman is to undergo gynecologic surgery that can cause infertility, she may want to freeze her eggs before the procedure.
• Cancer: Women diagnosed with cancer may choose to preserve their future fertility before cancer treatments such as radiation therapy, chemotherapy and surgery, which can cause infertility. Freezing eggs before undergoing cancer treatments is called oncofertility.
• Some patients choose to freeze eggs prior to starting hormones or surgery for gender reassignment.

Social reasons to freeze eggs

The Veterans Administration now covers fertility preservation for social reasons.

Egg preservation through the cryopreservation process

Freezing eggs involves all the steps of the in vitro fertilization (IVF) process, but on a different timeline. Both begin with ovulation induction (injections) and egg retrieval, at which point the eggs are then cryopreserved. Once the patient is ready to utilize the eggs, the IVF process continues. The eggs are thawed and fertilized, and the resulting embryo(s) are transferred into the woman’s uterus.

Ovarian reserve assessment

Our fertility specialist will perform an ovarian reserve assessment to estimate the potential number of eggs that might be available before the ovarian stimulation cycle. This assessment will include a pelvic ultrasound as well as blood tests, which will help determine the correct dose of ovulation stimulation medications.

Ovulation induction

Ovulation induction, also known as controlled ovarian stimulation (COS), uses injectable fertility medications for 10 to 12 days to stimulate the woman’s ovaries and increase the number of eggs available. The goal is to safely collect and freeze as many eggs (oocytes) as possible.
The number of eggs a woman should freeze varies by age, as follows.

Women under 35: Freeze 20 mature eggs for an 85% chance of having at least one child.

Women 38 to 40: Freeze 30 mature eggs for a 75% chance of having at least one child.

Women 41 to 42: Freeze 30 mature eggs for a 50% chance of having at least one child.

Egg retrieval

After stimulation, the eggs are retrieved from the ovarian follicles while the woman is under mild anesthesia. This in-office procedure uses a long needle carefully inserted through the vagina and guided by ultrasound. The maturity of the retrieved eggs is then evaluated under the microscope and selected mature eggs are frozen using vitrification.

Egg vitrification (freezing) & thawing for fertility treatment

During the freezing process, one of our expert embryologists applies a solution that prevents crystals from forming in the eggs. The eggs are then cooled to subzero temperatures, and then safely stored in a cryotank (usually with liquid nitrogen) until they are thawed to be fertilized.

Unlike embryo cryopreservation used in IVF, the eggs are not fertilized prior to freezing. Once a patient is ready to use the eggs, they are placed in a warming solution to rapidly thaw. The thawed eggs can then be fertilized and transferred into the uterus to achieve pregnancy.

Risks of egg freezing

There are a few risks involved with the egg freezing process including ovarian hyperstimulation syndrome (OHSS), surgical complications and emotional side effects of going through treatment.

Fortunately, physical risks or complications are rare. Our fertility specialists thoroughly discuss these risks ahead of time with all patients, making sure to answer all their questions and helping them to completely understand the process.

Medical risks include:

• OHSS can occur when ovulation induction medications cause swollen or painful ovaries, nausea, bloating and some abdominal pain.
• The egg retrieval process carries the same basic risks as any other minor surgical procedure including infection, bleeding and other anesthesia-related complications.
• Although very rare, the needle used to collect the eggs can damage the bowel, bladder or a blood vessel.
• Eggs may be damaged during the freezing or thawing processes.
• Emotional risks are also possible as patients may experience false hope.

Egg freezing can provide a fertility safety net but there is never a guarantee of pregnancy ending in live birth. Patients should be aware that even with healthy eggs, pregnancy may not be achieved.