“This is Marina. She leads a feminist organization.” This is how I am introduced at the entrance of an event that aims to “normalize egg freezing,” run by a startup collaborating with a private fertility clinic. It’s a misunderstanding, but for a moment I contemplate whether that’s what I should be doing, and my mind wanders.

The event is taking place at a private members’ club in a bougie part of London. We are gathering on pastel-colored chairs, and the air in the room feels like cold wool. I sit and listen, alongside other women, as if I’m here to learn about my fertility, as if I am wondering whether to freeze my eggs. I’m here to find out how the organizers talk about egg freezing. It’s research for my book on women’s health innovation, The Vagina Business.

In the US, some clinics throw “egg freezing parties” with champagne and canapés. They create a sense of solidarity around “taking control” of our “biological clock.” Pop-up buses offer free fertility tests. Whenever a company hands something out for free, it’s worth considering their business model and whether you are about to become the product. There is no champagne at the event I have come to, and despite the buoyed empowerment language on the invitation, the mood is gloomy.

The women in the audience are in their twenties and thirties, almost exclusively white, clad in black leather skirts and cashmere sweaters. We’re asked to fill out a survey, and the woman in front of me puts her copy beneath her chair, so the moment I look down at my feet, I can’t help seeing that she earns between £70,000 and £100,000 annually ($94,000 and $134,000). That’s more than double the average income of a Londoner.

The fertility clinic presenter says, “I fully appreciate that thinking about fertility is something that feels overwhelming.” She says that while women are good at eating well and exercising, we neglect our fertility. “Those aren’t easy conversations to have.” With urgency in her voice, she says the conversation we are about to have is still easier than conversations she has with clients who have struggled to conceive for years and have run out of options. She congratulates the audience for taking the first step to understanding their fertility by attending this event.

And herein lies the first problem. Fertility is not part of our education, and not a topic that health providers routinely address. That, however, means anything the presenters say could be accepted as fact. Women who have come to learn about their fertility for the very first time are in a vulnerable position.

How Many Eggs Do I Need to Freeze?

One woman in her thirties, who sits in the audience, asks how many eggs she would need to freeze to have a child later on. “I promise I’m not trying to be coy—it’s really hard to answer questions about the success rate,” says the presenter. She says some clients only had one egg retrieval cycle—that might yield a few eggs—and that is fine.

At that point, I’d like to hand the inquirer an evidence-based chart on the number of eggs she needs to freeze. Just a few eggs are a bad idea. But I realize that if I produce a research paper out of my tote bag, in the eyes of the audience, the presenters run a clinic, and I’m just an unknown woman with a bright orange umbrella.

For women below the age of 35, freezing 20 eggs provides a 90 percent chance of a live birth. At the age of 38, one would need 40 eggs for a 90 percent chance. A larger number of eggs typically means multiple rounds of egg retrieval.

A lot of what the presenters say is factual, but the danger is in the detail. They imply that having a low ovarian reserve—which is assessed through the fertility tests they sell: the anti-Müllerian hormone (AMH) test and antral follicle count—means you should freeze your eggs to avoid disappointment further down the line. It’s a fear-based claim without any nuance.

What Does the AMH Test Tell You?

It’s worth knowing that the AMH test was developed in the context of reproductive technology. It wasn’t originally intended as a routine test, and it doesn’t reliably predict fertility. It does not tell you whether you can get pregnant or whether to freeze your eggs.

An ovary contains follicles, which are tiny, fluid-filled sacs. Each follicle contains an immature egg. In the first half of the menstrual cycle, hormones trigger a few of these follicles to grow, but only one follicle goes all the way to maturity, while the rest of the cohort gets expelled through what’s called “apoptosis.” It’s typically only the dominant follicle that releases an egg at ovulation, and the egg goes on to travel down the fallopian tube, ready to fuse with sperm.

Through medication, it’s possible to stimulate the ovaries to produce multiple eggs to then retrieve them for IVF or egg freezing. Looking at AMH levels can help us estimate how many follicles could be stimulated to grow mature eggs for that purpose.

But having a low AMH level relative to your age group doesn’t mean you’re less likely to conceive naturally. Because one egg typically gets released by one of your ovaries each month regardless of AMH levels.

The AMH level matters if you plan to have children at an advanced age, as a low AMH can indicate a slightly earlier onset of menopause. Some research has shown that if your AMH level is in the bottom 5 percent, your menopause age is 49, on average. If your AMH level is in the top 5 percent, then the median age is 55.

AMH looks at the quantity, but we have no way to assess egg quality. For conception, egg quality is crucial. And age is an important factor for egg quality. But clinics couldn’t possibly charge for consultations where all they do is point out your age.

Tests are useful in that they can help to diagnose conditions like polycystic ovary syndrome (PCOS) or an underactive thyroid, which can affect fertility. But if a test is used to sell something else, it’s worth questioning what that next product is or does. Beware if anything you are sold triggers strong emotions of fear—you’re running out of eggs!—scarcity, and pressure. Clinics can present you with an accurate test result, but that’s not the same as an accurate interpretation of the result.

Where’s the Full Picture?

The age 35 is often seen as a fertility cliff for women. It’s true that female fertility peaks between our late teens and late twenties and it does decline more steeply after 35. But statistically it declines in a slope—it does not fall off a cliff—and there are individual variations.

Egg freezing can preserve eggs that are statistically likely to be of a higher quality at a younger age for a pregnancy at a later stage—though it’s physically more demanding to carry a pregnancy at a later age, and the risk of gestational diabetes, for instance, increases.

What’s more, when frozen eggs are thawed, their survival rates vary by clinic. The presenters emphasize that 95 percent of eggs they have frozen at their clinic survive the thawing process. But that figure is just one of many factors that need to be considered.

The egg has to survive freezing, storage, and thawing; it has to be genetically viable; it has to fertilize; and the pregnancy has to work out—there are many steps on the way. According to the American Society for Reproductive Medicine, the chance for a single egg resulting in a birth is between 2 percent and 12 percent.

The presenters never use the word “IVF” or “ICSI” (Intracytoplasmic Sperm Injection) even though a fertility treatment is the logical conclusion of freezing your eggs. They therefore omit that such a treatment carries an additional price tag and that resulting pregnancies tend to be higher risk.

Success rates vary. Out of 2.5 million IVF cycles performed around the world per year, about 500,000 result in a birth. That means 80 percent of IVF cycles don’t succeed.

They also don’t mention potential side effects of the medication that’s used to stimulate the ovaries for egg retrieval, such as headaches, fatigue, cramping, and nausea, and they don’t mention rare but potentially serious complications such as ovarian hyper-stimulation syndrome. At one point, they say they don’t want to get “too technical.” But if I were planning to freeze my eggs, I would like to know the evidence, risks, and cost up front.

Egg freezing is an expensive procedure, although prices vary by geography. One cycle of egg freezing can cost $10,000 in the US and £7,500 in the UK. The cost can be as low as €2,750 in Spain, not dissimilar from a full set of Invisalign braces. It’s not surprising Spain has already become an egg-freezing tourism hub.

There are multiple components that make up the cost of the procedure. There’s the consultation, medication, blood tests and screening, as well as the actual egg retrieval and freezing cycle or, more likely, several cycles. The second part is the egg storage fee, which is typically annual, and the third part is the transfer of the eggs to attempt a pregnancy once they’re thawed. It’s often the case that fertility clinics don’t reveal all the costs involved up front.

Modern reproductive technologies like IVF and egg freezing are worth celebrating, as they help millions of people start a family in a way that was impossible in previous decades. They can be a lifeline. The reason I focus on the nuances and risks here is that the space urgently needs more regulation and transparency: We deserve the full picture.

No Longer Experimental

Egg freezing—or its technical name, “oocyte cryopreservation”—was developed in the 1980s, to be used for medical reasons. The idea behind “medical egg freezing” is to preserve the eggs of someone who is about to have a fertility-threatening procedure. It can be a protective measure against chemotherapy, which diminishes fertility, as well as conditions including autoimmune disorders and severe endometriosis. It is also used by trans men who would like to preserve their fertility.

With the development of “vitrification”—a more reliable freezing technique—egg freezing was commercialized for nonmedical reasons. In 2012, both the American Society of Reproductive Medicine (ASRM) and the European Society of Human Reproduction and Embryology decided to lift the “experimental” label of egg freezing.

Since then, “social egg freezing” has been on the rise. Kim Kardashian froze her eggs. Jennifer Aniston has said she regrets not freezing her eggs. On TikTok, influencers upload videos of their daily injections and reels about their trips abroad to have their eggs frozen.

Every woman is different when it comes to how age affects her fertility. Some women do not suffer infertility in their early forties. Egg freezing typically works best for those in their twenties and thirties and is not usually recommended for women over 38 years, according to ASRM. And yet, research shows that the average age of egg freezing in the UK and United States is 38. The main motivation is to “buy time” to find a partner, according to research done at Yale University.

The procedure involves daily injections for about 8 to 14 days to stimulate a group of eggs to mature and develop. During this time, ultrasounds and blood tests determine whether the medication is working. Retrieving the eggs is usually done under general anesthetic or sedation. Once the eggs are inspected by an embryologist and deemed usable, they can be frozen.

“I often hear the phrase ‘this is insurance,’” Timothy Hickman, the former president of the Society for Assisted Reproductive Technology (SART), told me. But that’s misleading. “Life insurance is a policy: If you need it, it pays off; this may not pay off.”

Whether venture-backed startups are a positive addition to the fertility space, depends on whether they show people the full picture. Or whether they maximize their profits by making fear-based claims.

What would be truly revolutionary is to find ways to bring down the prices of fertility treatments and make them transparent and accessible to all, ideally covered by healthcare, as is already the case in some countries.

The Future of Egg Freezing

For now, our data on egg freezing is limited, while the uptake continues to increase. Most studies showing successful pregnancies with frozen eggs focus on donor eggs. We do not have large-scale data on women freezing and using their own eggs, because most eggs frozen recently haven’t been thawed yet.

In a few decades’ time, egg freezing might look radically different. The procedure might become so safe, accessible, and effective that women in their twenties confidently freeze a small number of eggs to preserve their quality just in case.

Clinics vary in how good they are at fertilization. The air quality inside the laboratory matters. Shining a red light on sperm cells improves their performance—they seem to like the spotlight—and a petri dish covered in a thin layer of diamond can help. All of this could improve the process.

Egg freezing could also fall out of favor for cultural reasons, if governments introduced better childcare policies and addressed wealth inequalities and if workplaces acknowledged the importance of families, so that people no longer delayed having children and being a single parent would become easier. It’s very sad that this scenario seems less likely than the technology-focused ones.

Alternatively, the procedure may no longer exist, because it’s been replaced by another technological advance. In 2023, researchers at Osaka University in Japan led by Professor Katsuhiko Hayashi managed to turn the stem cells of male mice into egg cells. These egg cells were implanted in female mice who gave birth to seven babies. Perhaps, this could eventually translate into human research. Or perhaps, scientists find a way to shield our egg quality from declining with age.

Excerpt adapted from The Vagina Business: The Innovative Breakthroughs that Could Change Everything in Women’s Health by Marina Gerner. Copyright 2024. Published with permission of Icon Books.