You're born with a finite number of eggs. This number, as well as the quality of the eggs, decreases with age — an unfortunate reality that impacts your fertility over time.
And whether the commentary is coming from a voice in the back of your mind or a family member sitting across the dining table, thinking about your biological clock can be the source of much angst.
"There are many reasons a woman in her late 20s or early 30s might be thinking about fertility preservation and egg freezing," says Dr. Kathleen Mundy, an OB-GYN at Houston Methodist. "She may be trying to coordinate the timing of family planning with career planning or still waiting for the right partner to come along. Egg freezing can help preserve fertility, but making the decision to freeze your eggs is a bit more complicated than it might initially sound."
If you're not ready to start — or grow — your family just yet, but getting pregnant in the future is the plan, Dr. Mundy has the answers to your questions about how egg freezing works and what to consider in deciding if it's the way to go.
How does the egg freezing process work?
"Egg freezing, which is also called mature oocyte cryopreservation, is the process of harvesting eggs from your ovaries and freezing them until you are ready to try to get pregnant," explains Dr. Mundy.
To retrieve your eggs, you first undergo about 10 days of hormone injections. This part of the process is similar to preparing for in vitro fertilization (IVF).
"The hormones injected are fertility drugs that stimulate ovulation and help your ovaries mature several eggs at once, instead of just one," says Dr. Mundy. "Mature eggs are then collected through a painless procedure performed while you are sedated. It's best if at least 10 eggs can be harvested."
Once retrieved, the eggs are flash frozen and stored at ultra-cold temperatures.
When you are ready to try for pregnancy, the eggs are thawed and combined with sperm. Any embryos that develop are then transferred to the uterus for implantation.
When should you consider freezing your eggs?
Put simply, the younger you are when you freeze your eggs, the better your chance of becoming pregnant through this process.
"As far as when exactly is the best time for a woman to freeze her eggs, that's a bit complex," says Dr. Mundy. "Studies suggest that women who freeze their eggs before age 35 have a better chance of a successful pregnancy than those who freeze their eggs after age 35."
This is because the more eggs retrieved and frozen, the better the chance of a successful pregnancy. And while the number (and quality) of eggs a woman has can vary, age is often the most commonly used predictor of how successful the whole process is likely to be.
"I often talk to my patients who turn 30 about this option, when egg quality and quantity start to decline," adds Dr. Mundy.
If you're worried about your fertility, your doctor can perform imaging and blood work, such as an anti-müllerian hormone (AMH) test, that help determine your egg quantity and quality, in addition to predicting how well you might respond to hormone injection therapy and how your ovaries are currently functioning.
"Anti-müllerian hormone is not a perfect indicator, but it helps estimate if a person has a high, normal or low amount of eggs," says Dr. Mundy. "It also predicts how successful egg retrieval may be."
What to consider before egg freezing?
At first thought, egg freezing might seem like a no-brainer for a young woman who isn't yet ready to have kids.
But here are four things Dr. Mundy says a woman should know before deciding to freeze her eggs.
1. The egg freezing cost
The thing with egg freezing is that you are quite literally buying time.
"Possibly the largest hindrance to egg freezing is how expensive it is, typically costing at least $10,000 and sometimes reaching nearer to $20,000," says Dr. Mundy. "Yes, freezing your eggs when you are younger can make the process more successful. However, the younger a woman is, the more likely she is to not need the eggs she freezes either."
It begs the question: When does the very high price tag become worth it?
A 2015 study weighing the probability of success with the total cost and possibility of never using the eggs found age 37 to be the most optimal time to freeze your eggs.
2. Taking fertility drugs comes with side effects
Hormone injections help your ovaries produce the optimal number of mature eggs it can take for the process to be successful. But the fertility drugs come with some fairly unpleasant side effects, including:
- Nausea and vomiting
- Mood changes, anxiety and depression
The hormone injections themselves also are not entirely devoid of a side effect risk.
"These injections on rare injections also can cause ovarian hyperstimulation syndrome, which is when the ovaries swell and become painful," warns Dr. Mundy.
Dr. Mundy also reminds women that the entire egg-freezing process will require making time for a few rounds of blood work and ultrasounds.
3. Egg retrieval is a medical procedure that comes with risks
During the process, eggs are retrieved using transvaginal ultrasound aspiration, which uses an aspiration needle.
"Complications from this procedure are rare, but they can include bleeding, infection and potentially even damage to the bladder or bowel," says Dr. Mundy. "This is not a reason to avoid egg freezing, but it's important to understand that egg retrieval is a medical procedure that, like all procedures, comes with risks."
4. There's no guarantee of successful pregnancy
Egg freezing can increase the likelihood of a future pregnancy, but it isn't a sure thing.
"The overall success rate of egg freezing varies based on a number of factors," explains Dr. Mundy. "For instance, the quality of your eggs cannot be determined during egg retrieval, and your age can impact overall success. In addition, not every egg will survive the thawing process and, similarly, not all eggs will be successfully fertilized by the sperm."
Given these unknowns, Dr. Mundy stresses that women should not think of egg freezing as fertility insurance.
"It's so important to understand both the benefits and limitations of this process and be prepared to handle the emotional toll of egg freezing potentially not working for you," says Dr. Mundy.