Egg Freezing
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Egg freezing is a process in which a patient with ovaries chooses to go through the first few steps of the IVF process: preparation, ovarian stimulation, and egg retrieval (see IVF). Instead of fertilizing the eggs, the eggs are frozen for later use if needed.
What is the history of egg freezing?
Egg freezing was initially an experimental therapy developed for patients about to undergo specific treatments, like cancer chemotherapy, that had a high risk of causing infertility or sterility.
Egg freezing has been considered an established medical procedure since 2012 when the American Society of Reproductive Medicine (ASRM) removed the experimental label from egg freezing.
The use of egg freezing has increased dramatically and gained popularity since.
In the early years, eggs didn’t survive the freeze thaw process well, however as techniques in the embryology lab have evolved, frozen eggs, particularly for patients less than 37 years old at the time of freezing, are now similar to fresh eggs.
Why do people freeze eggs?
Egg freezing is used to increase the chance that future IVF, if needed, will be as successful as possible.
Age is the greatest predictor of fertility, thus the younger a patient is when their eggs are frozen, the higher the likelihood of conceiving from those frozen eggs will be. However, the greatest limitation is that it is hard to predict when and how many children you might have.
It is also difficult to predict precisely when an individual person will be infertile from ovarian aging. We do know for certainty that the younger the eggs are in IVF, the higher the chances of having a baby are.
For most people, ovarian aging is gradual in their 20s and early 30s and exponential starting around 35-37 years of age, with the most rapid change occurring in their 40s.
After your eggs are frozen they will be kept in long term storage and if you need to use those eggs for IVF they will be thawed out and fertilized with donor or partner sperm using ICSI.
Other risks of infertility that freezing eggs may mitigate include:
Prior to chemotherapy, if chemo presents a risk of ovary damage.
Prior to surgery, if surgery presents a risk of ovary damage.
Prior to surgery to remove the ovaries, for BRCA carriers or gender affirmation surgery.
Prior to gender affirming hormone treatment.
Known genetic risks of early menopause such as turner syndrome or fragile x syndrome.
Suspected increased risk of early menopause, such as a strong family history of early menopause or a severely low ovarian reserve (although severely low ovarian reserve does not predict the time to menopause well).
Diseases with an increased medical risk for IVF such as endometriosis or known fallopian tube disease.
What are the steps of egg freezing?
Egg freezing comprises the initial three stages of the IVF process, with a postponement of the fertilization and embryo transfer phases. Those steps are:
Preparation: Preparing for egg freezing takes a variable amount of time. Patients need to emotionally, socially and physically prepare to start stimulation. Some protocols require medications during preparation (priming) and some patients may choose to optimize their lifestyle during this time. Some patients may choose to go through one cycle no matter what the anticipated results may be while others may plan to go through several cycles in order to achieve what they consider is an optimal result. It is important to note that there is no treatment that can majorly change the number of eggs retrieved per cycle. Ovarian reserve testing will be used to help predict an expected range of eggs that may be retrieved per cycle.
Ovarian Stimulation: During ovarian stimulation, patients take medications that stimulate the simultaneous production of multiple eggs in the ovaries. This often involves 2-3 injections each day, using very small needles, or a combination of oral medications and injections for approximately 9-14 days depending on the stimulation protocol. During this time the growth of the eggs is monitored by vaginal ultrasounds and hormonal blood tests.
Egg Retrieval: An egg retrieval is a minor surgical procedure where the eggs are retrieved from the ovaries using a long thin aspiration needle and suction. Most commonly, anesthesia is given to avoid pain and discomfort, then the needle is placed through the vagina under ultrasound guidance, directly into each ovary. This procedure typically takes 15-30 minutes and is an outpatient procedure, meaning patients typically do not need to stay in the hospital overnight.
After the first three steps those eggs are frozen in the lab using vitrification, where the eggs are rapidly frozen using liquid nitrogen. The eggs are then kept in liquid nitrogen and are thawed if/when patients desire to use them to attempt to conceive.
additional resources
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what is the difference between egg freezing and embryo banking?
egg freezing and embryo banking are both forms of fertility preservation through cryofreezing. embryo banking is becoming a more frequent choice, particularly for young couples just starting their careers. egg freezing is the process of cryopreserving unfertilized eggs while embryo banking is cryopreserving already fertilized eggs. some patients choose for a combination of both egg and embryo banking. the egg and embryo banking processes start like the traditional ivf process. medications are prescribed to stimulate the ovaries to mature multiple eggs at once that can then be retrieved and frozen. in women who have cancer, ovarian stimulation protocols are tailored to each patient’s medical needs.
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how are the eggs removed through the outpatient procedure?
your doctor will use an ultrasound to identify where your egg clusters are. by now you’ve been on ivf medications for 8-10 days so you should have plenty of eggs. your doctor will use a needle attached to a catheter to gently pierce the vaginal wall. the eggs will be removed 1 by 1 with light suction. your eggs will be collected tubes that are labeled with your name and unique identification number. the eggs will then be transferred to the adjoining embryologist. your doctor will then examine your vaginal wall and ovaries. you may bleed a little and some instances the doctor may cauterize the area. no stitches involved.
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how are the eggs fertilized?
before a man’s sperm can fertilize a woman’s egg, the head of the sperm must attach to the outside of the egg. once attached, the sperm pushes through the outer layer to the inside of the egg (cytoplasm), where fertilization takes place.
sometimes the sperm cannot penetrate the outer layer, for a variety of reasons. the egg’s outer layer may be thick or hard to penetrate or the sperm may be unable to swim. in these cases, a procedure called intracytoplasmic sperm injection (icsi) can be done along with in vitro fertilization (ivf) to help fertilize the egg. during icsi, a single sperm is injected directly into the cytoplasm of the egg.