Egg freezing can be beneficial for women who wish to preserve their fertility for the future, whether this be because they want to focus on their career, have been diagnosed with an illness or are doing so for religious or moral reasons.
Women are born with two ovaries, each containing resting eggs or follicles. Every woman is born with a set amount of eggs. At 20 weeks gestation, a woman has about 6 million eggs, the most eggs she will ever have in her lifetime.
At birth, she will lose approximately half of her eggs, and by the time she reaches puberty, she has only about 200,000 eggs left in her ovaries.
During a menstrual cycle, one egg matures while the remaining eggs that are present that month degenerate.
Ideally, eggs should be frozen when a woman is in her twenties; her prime reproductive years. However, this isn’t always the case, as many women aren’t even thinking about children between these years! Patients who choose to freeze their eggs when they are under 35 tend to have higher success rates than those who are aged 35 and over.
Although sperm and embryos are easy to freeze, the egg is the largest cell within the human body and contains a large amount of water. This means that when it is frozen, ice crystals can form that destroys the cell. Embryologist using some techniques dehydrates the egg and replaces the water with some type of cryoprotectants prior to the freezing process to prevent the ice crystals from forming and damaging the cell.
To harvest the eggs for freezing, the patient undergoes hormone injections as done in any regular IVF cycle.
The only difference between the two procedures is that after egg retrieval they are frozen for some time before they are thawed, fertilized and transferred to the uterus. The egg freezing cycle takes around two weeks to complete. The process includes 10 -15 days of hormone injections to stimulate ovaries and achieving adequate response as to harvest 10-12 eggs from the ovaries.
Once the eggs have matured and follicle have reached 18-20 mm size, they are removed with a needle placed through the vagina under the guidance of an ultrasound. This procedure is not painful and is done under IV sedation. Eggs are quickly frozen and kept at -196 degree temperature.
When the patient is ready to start her family the eggs are thawed and injected with a single sperm to achieve fertilization. Resulting embryos are then transferred to the uterus as done routinely.
Scientific evidence suggests that long-term freezing of eggs does not result in any decrease in quality.
It is recommended that ten eggs should be frozen for each pregnancy attempt.
There is a variation across these figures depending on many factors, including competence of the embryologist and age of the patient. Younger women can be expected to produce more than ten eggs. Younger eggs would have higher chances of implantation than eggs of elderly women.
The age of the woman at the stage of thawing and implantation has an insignificant impact upon the overall outcome.
Depending on the age of the egg at freezing, each cycle would have a 15-30% chance of leading to a live birth.
It is recommended that 10 eggs be stored for each pregnancy attempt. 2-3 cycles may be done and adequate no of eggs be frozen for latter use.
The chance of future IVF pregnancy with her frozen eggs in women older than 38 at the time of freezing is likely to be lower than that seen for younger women.
To date, approximately 5,000 babies have been born from frozen eggs. The largest published study of over 900 babies from frozen eggs showed no increased rate of birth defects when compared to the general population. Additionally, results from one study showed no increased rates of chromosomal defects between embryos derived from frozen eggs compared to embryos derived from fresh eggs.
The costs for egg freezing are identical to those of routine IVF. In general, it costs 1.8 lac INR to undergo an egg freezing cycle. This estimate includes all testing, monitoring, medications and egg freezing.
The egg-freezing fee includes the storage fee up to the end of the calendar year. There will be afurther annual storage fee beginning January 1st of the next full calendar year.