The number of frozen eggs needed for IVF success varies by age, ovarian reserve, and overall fertility health. On average, 10–20 mature eggs may be required to have a reasonable chance of achieving a live birth.
Age plays a critical role in determining egg quality. Women under 35 generally require fewer eggs compared to older women, who may need more due to higher rates of chromosomal abnormalities.
Ovarian reserve tests, such as AMH levels and antral follicle count, help estimate how many eggs may be necessary for future IVF attempts. These assessments guide individualized fertility preservation strategies.
Cryopreservation techniques ensure high survival rates of thawed eggs. However, not all retrieved eggs will fertilize or develop into viable embryos, which is why fertility specialists recommend banking multiple eggs.
What is egg freezing?
Unfertilized eggs can be stored by using the egg (oocyte) freezing technique, which enables a woman to try getting pregnant at a later time when natural conception may be less possible. It can give women the choice of preserving their fertility who are unable to conceive right away or whose fertility is at risk due to medical conditions, such as cancer treatment.
Eggs that have been frozen can be kept for a long time without suffering much damage. The eggs are thawed when the lady is ready to use them, and the sperm is then injected into the thawed egg (ICSI). The developed embryo from the fertilized egg is then examined in the lab before being implanted into the woman’s uterus to achieve pregnancy.
Who can consider freezing eggs?
You might think to consider freezing eggs:
- If a severe sickness, such as cancer, endangers your fertility;
- If you want the chance to start a family after the age at which fertility normally declines and are not now in a position to do so.
- If you’re thinking about donor insemination (for a more immediate pregnancy rather than a delayed pregnancy), storing your eggs or embryos, or if your own ovarian function is anticipated to decline.
How is the egg-freezing process?
Egg freezing process contains 4 steps:
- Hormone stimulation of your ovaries
A woman is typically given hormonal stimulation for 10 to 12 days to get eggs that will be frozen, allowing multiple eggs (typically 6 to 15) to mature. There are numerous stimulation methods, and after reviewing your options with your professional, you will choose the one that is best for you.
- Egg collection
When your eggs are ready to be harvested, an ultrasound-guided probe that is placed into the vagina is used to extract the eggs from your ovaries without making any cuts or leaving any scars. To aspirate eggs from each ovary, a needle is gently inserted into each one through the probe and into the vaginal wall.
- Vitrification
Through a process known as vitrification, the eggs are frozen. This involves a quick freezing technique that protects eggs from potentially harmful ice crystal development. Eggs can be vitrified and kept for a long time under liquid nitrogen.
- Using your frozen eggs
When the moment is right, your eggs are removed from the freezer and swiftly defrosted in specialized solutions. Normally, it is prepared for fertilization by a single sperm being injected into the egg (ICSI). The egg develops into an embryo after fertilization, and if the uterine lining is successful, embryo transfer is carried out.
What are egg-freezing success rates?
Since vitrification for egg preservation is a relatively new technique, it is still too soon to provide exact odds for pregnancy following vitrification, future thawing, and fertilization. The age of the woman at the time of the procedure heavily influences the likelihood of success.
The success rates of egg freezing are expected to be:
- A boosted cycle will yield 10–12 eggs for a woman under the age of 35, of which 7-9 will be suitable for vitrification and storage.
- In the future, warming will allow between 70–90% of the eggs to survive.
- About 50–80% of the eggs that survive are fertilized.
- Approximately 50–90% of fertilized eggs create embryos.
- There is a 20–35% probability that one embryo will result in a pregnancy.
How many frozen embryos does it take to have one baby?
More than one embryo can be created after a successful IVF cycle, and some people choose to save the extra embryos for future family planning. Pre-implantation genetic testing (PGT) patients also typically freeze their embryos because it takes more than a week to get test results. Freezing embryos is also a technique that can help preserve future fertility for those who have undergone hormone therapy, cancer treatment, sex-affirmation surgery, or other medical procedures that may affect their fertility.
The number of frozen embryos required to have a baby can vary depending on several factors, including the age and fertility of the person receiving treatment, the quality of the embryos, and the expertise of the medical team performing the procedure.
Factors such as the number of embryos transferred in a single cycle, the quality of the embryos, and the number of frozen embryos available for use can all affect the success rate of frozen embryo transfer.
As a result, the success of frozen embryo transfer and the number of embryos required to have a baby will depend on many individual factors and it is important to discuss your specific situation with your doctor or a fertility specialist.
Source:
Van de Wiel, L. (2020). The speculative turn in IVF: egg freezing and the financialization of fertility. New Genetics and Society, 39(3), 306-326.
