This post was originally published on this site
Though the technology for freezing an embryo has existed since the 1980s, preserving an unfertilized egg was a technical challenge that most scientists didn’t think was worthy of solving. In the late 1990s, however, researchers from around the world found a way to freeze and thaw an egg without damaging it.
In the early 2000s, fertility doctors in the United States conducted clinical trials to replicate the method. By 2012, there was strong evidence that the procedure led to fertilization and pregnancy rates that were similar to in vitro fertilization, convincing the American Society for Reproductive Medicine to stop considering it an “experimental procedure.”
Without the label, insurance companies could cover the procedure, paving the way for tens of thousands of women to extend their fertility by freezing their eggs. Almost 20 percent of U.S. companies with more than 20,000 employees offer coverage for egg freezing, up from 6 percent in 2015, according to a national survey by Mercer, a corporate benefits consulting firm.
But even as egg freezing has grown more popular over the last decade, the process can seem intense and overwhelming. Here’s what you need to know.
What is egg freezing?
Women are typically born with around one million eggs, a number that steadily decreases with age. Oocyte cryopreservation, the technical term for egg freezing, is the procedure through which eggs are harvested, frozen and stored for later use.
When preparing for egg retrieval, patients take hormones to stimulate the ovaries, prompting them to grow multiple follicles (fluid-filled sacs that each house an egg). Once the follicles reach a certain size, a fertility specialist will retrieve the eggs, freezing only those that are ready to be fertilized. The entire process unfolds over about two weeks.
What is the process like?
First, fertility specialists conduct a blood test to estimate the patient’s current egg supply. They might also administer an ultrasound to measure follicles and ensure that the ovaries can be easily reached during the egg retrieval.
Some doctors may direct a patient to take hormonal birth control before starting fertility medication to improve the chances that follicles grow together at around the same size and rate. Fertility centers tend to have their own birth control preferences and policies, said Dr. Mindy Christianson, medical director of the Johns Hopkins Fertility Center.
Women undergoing the egg freezing process inject themselves with hormone medication one or two times each day. These shots, administered for around eight to ten days, stimulate the follicles to grow.
Patients visit their doctor’s office every few days to measure those follicles and test estrogen levels. The bigger a follicle is, the more likely it is to contain a mature egg, said Dr. Amanda Adeleye, a reproductive endocrinologist and assistant professor at the University of Chicago. Although a woman may have thousands of eggs, “most of them are not going to respond to the medication,” she said.
About a week into the process, patients take medication that blocks ovulation, so that eggs are not released before they can be retrieved. Then, once the follicles reach a certain size, patients give themselves a “trigger shot,” that releases the eggs in preparation for egg retrieval, said Dr. Elliot Richards, director of reproductive endocrinology and infertility research at the Cleveland Clinic.
About 35 hours after the trigger shot, doctors perform the egg retrieval, draining each follicle by inserting a small needle through the vaginal wall and maneuvering it within the ovary.
The procedure typically takes between 15 and 30 minutes, said Dr. Rachel Ashby, director of the Donor Egg and Gestational Carrier Program at Brigham and Women’s Hospital. And patients are generally sedated the entire time: “She doesn’t feel anything or remember anything,” Dr. Christianson said.
That day, doctors can determine how many eggs were retrieved. The average patient under 38 could retrieve 10 to 20 per cycle, but that number varies depending on the individual egg supply and the ovarian response to the medication.
Only mature eggs are frozen, through a process called vitrification: a type of flash freezing in which eggs are bathed in liquid nitrogen to prevent the formation of ice crystals, which could damage the eggs. Then, eggs might be kept at the center where they were vitrified or sent to another location for long-term storage.
What are the risks of egg freezing?
As with any medical procedure, egg freezing comes with side effects and risks. The medication that stimulates the ovaries can raise a woman’s estrogen level 10 to 20 times higher than it is during a regular menstrual cycle, Dr. Christianson said.
Some patients experience mood swings as a result of higher than normal estrogen levels. And, they might feel bloated as the ovaries enlarge from growing multiple follicles.
If someone has a history of blood clots, doctors may recommend a blood thinner while the patient receives medication.
A few days before egg retrieval, many patients experience discomfort. “They’re not going to feel great,” Dr. Richards said. “It’s not trivial.”
Bleeding and infection are risks of egg retrieval, but complications like this are not typical, he added.
Because of the anesthesia used during the retrieval process, some people may experience nausea and vomiting, which would be treated with medication, Dr. Ashby said. Patients might also notice abdominal pain after retrieval, which is often managed with ibuprofen or Tylenol, Dr. Adeleye said, adding that patients might want to take a day off work.
In rare cases, women may develop severe ovarian hyperstimulation syndrome, an adverse reaction to hormone medications that stimulate egg production. Their ovaries swell, causing small blood vessels to leak fluid, which can accumulate in the abdomen or, more rarely, around the lungs. The symptoms — which include bloating, nausea, and difficulty with urination and breathing — occur most prominently three to five days after the procedure, Dr. Adeleye said.
The condition occurs in roughly one percent of women who undergo egg freezing, and is more common in those with polycystic ovary syndrome because P.C.O.S. can increase the risk of developing too many follicles, which in turn can cause ovarian hyperstimulation syndrome, Dr. Christianson said.
Women who freeze their eggs at younger ages, in their early 20s, are also more at risk, Dr. Christianson said, because larger egg supplies are a risk factor for hyperstimulation. The more eggs a woman has, the higher the chance that the medication she takes before egg retrieval will stimulate a large number of ovarian follicles.
Doctors can carefully monitor patients and reduce ovarian hyperstimulation syndrome risks, but anyone considering egg freezing should be counseled on the danger of the condition, Dr. Christianson said.
How much does egg freezing cost?
Costs vary between fertility centers, but in general, a single cycle of egg freezing, including ultrasound monitoring and doctor supervision, can cost around $4,500 to $8,000, Dr. Christianson said. Patients typically complete one or two cycles, she added. Insurance coverage may vary depending on the type of plan a patient has.
The injectable medication, separately, costs between $4,000 and $6,000 per cycle, she said, depending on how much medication the patient needs.
Storing eggs is an additional cost — it can reach over $500 each year.
Who is a candidate for egg freezing?
Egg freezing is no longer an experimental treatment, but it’s not a fertility panacea either. One study of more than 500 women, published this summer, found that the overall chance of a live birth from frozen eggs was 39 percent. The findings also suggest that age and egg quantity contributed to the success rates: If a woman was younger than 38 or thawed more than 20 eggs, her chances increased significantly. Guidelines from the American College of Obstetricians and Gynecologists state that there is not enough research to support egg freezing solely to delay having a child.
Some experts, however, said that anyone at risk of age-related infertility could be a candidate. Other people who might seek out the procedure are those who are about to undergo chemotherapy, which could affect the ovaries, or people who identify as transgender or nonbinary and are considering gender-affirming hormones, Dr. Adeleye said.
“The eggs we retrieve right now, technologically, are the best way we have to preserve their fertility,” Dr. Ashby said. “But we will not know if those eggs will work until they use them.”