Why is egg freezing so popular now? Why didn't my mom or older sister freeze their eggs?
Egg freezing has become more accepted over the past few years as a method of fertility preservation for a number of reasons. Before 2013, anyone who froze their eggs had to do so under an experimental protocol. But after studying egg freezing in depth, the American Society of Reproductive Medicine issued a statement that there is enough scientific evidence showing that egg freezing works and that it should longer be considered experimental.
Two important factors influenced this position: First, new egg freezing technology was introduced called vitrification, a fast-freeze method that almost instantly transforms the eggs into a glass-like frozen state. Vitrification reduces the likelihood that the fluid in the egg will form ice crystals, which could damage it. Multiple studies of egg freezing done via vitrification demonstrated that it was much more successful than the older method called "slow freeze."
Second, a number of studies were done using donor eggs where it was reliably determined that pregnancy rates were essentially the same whether the egg obtained was fertilized without freezing (eg. fresh) or frozen first.
What is ovarian aging and how does this affect fertility?
Age affects a woman's eggs more than any other factor. Women are born with all of the eggs they will ever have, and at birth that's around one million eggs. Over time, eggs are lost through a natural process called atresia and others are lost when women ovulate in the middle of their menstrual cycle.
In additon, as women get older the quality of their eggs decreases.This is because as an egg sits in a woman's ovary, it has a greater chance of becoming damaged over time. An egg with abnormal chromosomes will be less likely to fertilize, and if it does fertilize, it will be less likely to result in a viable ongoing pregnancy. Typically the younger the woman, the greater both the quantity and quality of her eggs.
How can egg freezing prevent ovarian aging?
Egg freezing can't prevent ovarian aging, but once the eggs are removed from your body and frozen, they can no longer age. This means that if years later you decide to fertilize those eggs in a lab to get pregnant, your chances of achieving a successful pregnancy will likely be the same as if you'd fertilized those eggs in a lab at the time the eggs were frozen.
If a woman freezes her eggs, won't she reach menopause earlier because the eggs are taken out of her ovaries?
The answer is no. Depending on the individual, during a woman's normal menstrual cycle about 10-20 or more eggs "wake" from their resting state and undergo a process called follicular activation and recruitment. Most of those eggs don't make it through the cycle and die off in the natural process of atresia, but usually, one egg survives. It's that egg that ovulates or gets released in the middle of the month. In the process of egg freezing, no additional eggs are "awakened," meaning that only that group of eggs that would have naturally been used for ovulation or lost to atresia are now being frozen in time.
Do women who are on birth control pills, which prevents ovulation, keep their eggs longer and lose their fertility at a later age?
Again, the answer is no. Even though birth control pills prevent ovulation and prevent an egg from being released from the ovary during the month, the eggs are still lost through atresia.
What does the egg freezing process entail and how does it work?
The goal with egg freezing is to save the eggs in a given cycle that would have been lost in the natural process of atresia and ovulation. We do this using hormone injections for about 8-10 days. These hormones are naturally occurring and are essentially the very same ones that a woman's brain releases when stimulating the eggs in her ovary. These hormones are called gonadotropins. Because we want more than just one egg to develop, we have a woman take higher doses of these hormones than her brain would ordinarily produce.
During this period, a woman will have 5-7 short office visits, including blood tests and vaginal ultrasound exams. At these visits, we assess a woman's individual response to the medication and make adjustments depending on how the eggs are growing. We also give another medication to prevent ovulation before we are ready to retrieve the eggs.
Once the number and size of the eggs in the ovary are deemed sufficient, as determined by ultrasound and bloodwork, the retrieval process is performed. Patients are placed under mild anesthesia so they don't don't feel anything. The entire process takes about 15 minutes.
We use an ultrasound probe in the vagina attached to a needle. A very small puncture is made through the vaginal wall, which then enters the ovary. The fluid from follicles that enclose the eggs is sucked through this very thin needle. The fluid is then handed off to the embryologist in the embryology lab. The embryologist examines the fluid under the microscope to evaluate for the presence of the microscopic eggs and freezes the eggs that are mature and viable.
What is the recovery like?
Most women generally feel fine almost immediately the procedure. The needle used in the procedure is very small and usually, there is little or no bleeding afterward. Some women may feel a little crampy, which can be relieved with an over the counter ibuprofen or Tylenol. Most women feel good enough to go to work the next day; some may feel a little groggy from the anesthesia the day of the procedure but typically feel fine the next day.
Who should freeze their eggs?
If you're a woman interested in preserving your fertility and are considering having children in the future, but aren't currently interested in conceiving, then egg freezing may be considered.
Is there an age cutoff?
There is no official age cutoff, and as long as a woman is still menstruating and has not reached menopause, she is a candidate.
In general, the younger the woman the more -- and better quality -- eggs she will have. Typically, a woman gets the most number of healthy eggs before age 30, slightly fewer from 30-35 and then a smaller yield over age 35. So the younger the woman, the higher the chance of freezing a good number of eggs that may result in a pregnancy years later after freezing. This is because a younger woman will have a greater number of eggs altogether, and of that group, there will be a higher proportion with normal chromosomes than an older woman. This doesn't mean that an older woman can't freeze her eggs. It just means that an older woman may need more stimulation cycles to get the same number of good quality eggs frozen when compared to a younger woman.
How many eggs to freeze is a very individualized discussion. We will discuss the important factors -- age and hormone levels -- and we will discuss the chances that your frozen eggs will result in a pregnancy. Egg freezing does not guarantee pregnancy. But the more eggs that a woman freezes and the younger she is, the greater the chances for pregnancy.