Chapter 1: What is the optimal age to freeze eggs?
The optimal age to freeze eggs is 19. By Jean Smith. Published on February 8, 2026. If you're a woman interested in preserving your fertility window beyond its natural close in your late 30s, egg freezing is one of your best options. There's an image here. Description.
Graph showing monthly probability of pregnancy ending in birth by male partner age.
The female reproductive system is one of the fastest aging parts of human biology. But it turns out, not all parts of it age at the same rate. The eggs, not the uterus, are what age at an accelerated rate.
Chapter 2: How does egg freezing extend a woman's fertility window?
Freezing eggs can extend a woman's fertility window by well over a decade, allowing a woman to give birth into her 50s. In fact, the oldest woman to give birth was a mother in India using donor eggs who became pregnant at age 74.
In a world where more and more women are choosing to delay childbirth to pursue careers or to wait for the right partner, egg freezing is really the only tool we have to enable these women to have the career and the family they want.
Given that this intervention can nearly double the fertility window of most women, it's rather surprising just how little fanfare there is about it and how narrow the set of circumstances are under which it is recommended.
Standard practice in the fertility industry is to wait until a woman reaches her mid to late 30s, at which point if she isn't on track to have all the children she wants, it's advised she freeze her eggs. This is not good practice.
The outcomes from egg freezing decline in a nearly linear fashion with age, and conventional advice does a great misservice to women by not encouraging them to freeze eggs until it's almost too late. The optimal age to freeze eggs varies depending on the source and metric, but almost all sources agree it's sometime between 19 and 26. There's an image here.
Monthly probability of getting pregnant for couples not on birth control.
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Chapter 3: What are the common misconceptions about egg freezing?
Note that these couples weren't actively trying for pregnancy, which is why the absolute probability is so low. See figure A4 from Geruso et al. for context.
So why has the fertility industry decided to make freeze your eggs in your mid-30s the standard advice as opposed to freeze your eggs in your sophomore year of college? Part of the reason is fairly obvious. Egg freezing is expensive and college sophomores are not known for being especially wealthy.
Nor is the process especially fun, so given a choice between IVF and sex with a romantic partner, most women would opt for the latter. But another reason is that the entire fertility industry is built around infertile women in their mid to late 30s and most doctors just don't have a clear mental model for how to deal with women in their mid-20s thinking about egg freezing.
There are countless examples of this blind spot, but one of the most poignant is the fertility industry almost completely ignores all age-related fertility decline that occurs before the age of 35, to the point where they literally group every woman under 35 into the same bucket when reporting success metrics for IVF. There's an image here.
Chapter 4: Why is egg freezing recommended for women in their mid-20s?
Yes, you're reading this right. SART literally does not distinguish between 20-year-olds and 34-year-olds in their success metrics.
This is far from the only issue. We not only ignore differences between 24 and 34-year-olds, but the way we measure success in IVF is fundamentally wrong, and this error specifically masks age-related fertility decline that occurs before the age of 35.
If you go to an IVF clinic, create five embryos, get one transferred, and that embryo becomes a baby, you can go back two years later and get your second embryo transferred to have another child. If that works, your second child will be ignored by official statistics.
Births beyond one that come from the same egg retrieval are not counted, so these differences in outcomes that come from having many viable embryos literally don't show up in success statistics. This practice specifically masks the benefits of freezing eggs in your mid-20s instead of mid-30s, because most of the decline between those two ages comes from having fewer viable embryos.
What happens if we measure success differently? What if we instead measure the expected number of children you can have from a single egg retrieval and show how that changes as a function of age? There's an image here.
This figure was generated with a model built by embryo selection company Heresite. You can read their white paper on the model's construction here.
The answer is the difference between freezing eggs at 25 and freezing them at 37 becomes much more stark. There's a 60% decline in expected births per egg retrieval between those two ages, and no one in the IVF industry will tell you this.
Worse still, by age 35, over 10% of women won't be able to have ANY children from an egg freezing cycle due to various infertility issues which increase exponentially with age.
So for a decent portion of egg freezing customers, they will get no benefit from freezing their eggs and they often won't find this out until 5 to 10 years later when they go back to the clinic and find that none of the eggs are turning into embryos. Heading. Polygenic embryo screening. Freezing eggs at a younger age becomes even more important with polygenic embryo screening.
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Chapter 5: What are the risks associated with egg freezing?
It is possible to compensate for this to some degree by doing more IVF cycles, but by the late 30s when the modal woman is freezing eggs, even this strategy starts to lose efficacy. This is just one more reason why the standard advice to wait until your mid-30s to freeze eggs is wrong. Heading What about technology to make eggs from stem cells? Won't that make egg freezing obsolete?
More clued in people might point out that there are several companies working on making eggs from stem cells, and that perhaps by the time women who are 20 today reach the age at which they're ready to begin having kids, those eggs will be useless because it will be easy to mass manufacture eggs by that time.
There are three reasons why the possibility of stem cell-derived eggs should not give much comfort to women who want to preserve their fertility or have genetically enhanced children. Subheading. We don't know with certainty how long it will take to develop this technology. It's not trivial to develop eggs from stem cells.
One of the people running a company commercializing this tech believes the tech will be ready for human use in about six to eight years, but as always, there is significant uncertainty about exactly how hard each one of the required steps will be. Subheading Stem cell-derived eggs are probably going to be quite expensive at the start.
New technologies, especially those that go inside human bodies are pretty much always expensive and that will almost certainly be the case for stem cell derived eggs. The estimate I've heard from people in the industry is that eggs will probably cost $100,000 to $200,000 at the start.
There are many very wealthy women who desperately want biological children who will be willing to pay an incredible amount of money for just a few viable eggs made from their own cells. Early prices for stem cell-derived eggs will likely be an order of magnitude more than egg freezing.
And while I think that stem cell-derived eggs will eventually be cheaper than taking hormones and paying for a surgeon to extract them, that will take additional time. Subheading. Cells accrue genetic mutations over time. The cells from which we're planning to derive eggs accrue mutations over the course of your life.
So the older you are at extraction, the more de novo genetic mutations they will have accrued.
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Chapter 6: How do I actually freeze my eggs?
This is much less of a concern for normal oocytes because they have special mechanisms to prevent them from accruing mutation, eggs partially deactivate their mitochondria until they are ready to be matured, which cuts down on the number of mutations. But it is a much larger concern for blood stem cells like those that companies in the space plan to use to create these eggs.
Heading How do I actually freeze my eggs? I'll write a more complete guide on this later, but you can actually freeze your eggs for relatively little money if you know where to go. Clinics like CNY Fertility are about a third the price of a regular IVF clinic and have reasonably similar outcomes for procedures like egg freezing.
including the cost of the retrieval, monitoring, medications, flights, and hotels this will usually come out to about $6,000 to $7,000 per retrieval, most of the variance comes from flight costs and the cost of routine monitoring like ultrasounds. Storage fees generally run around $500 per year.
The downside of CNY is the customer experience is worse than average, and there's much less hand-holding than the average clinic. They aren't known for being particularly good with tricky infertility cases either, so if you've had past IVF failures you may want to look elsewhere. If CNY doesn't work for you, I'd recommend using Baby Steps IVF to find a clinic.
It provides ranked lists of the best clinics all over the United States, and it's completely free. Two friends of mine, Sam Solarik and Roman Hawkson spent the last year and a half building this site. It's probably the best resource on the internet for comparing clinics.
Most of the clinics you'll find through this website, and indeed most of the clinics in the country, will cost between $15,000 and $22,000 per round of egg freezing. If you're a California resident, check whether your insurance plan offers coverage for IVF. You may be able to get them to pay for egg freezing, especially if you are already married.
If you're rich and money is no object, the best IVF doctor I know is probably Dr. Amy. She's quite expensive compared to the average IVF doctor, somewhere between $25,000 and $40,000 per round with all expenses included, but she has produced some pretty outlierish results for a number of my friends and acquaintances.
One acquaintance of mine got 17 euploid embryos from a single egg retrieval which is one shy of the most productive IVF cycle I ever saw while at Genomic Prediction. She seems to be particularly good for women with tricky infertility cases, though again this is based on a small sample size and there is no guarantee of outcomes.
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Chapter 7: What future technologies could impact egg freezing?
Most women will need 1 to 3 rounds of egg retrieval to have a high chance of having all the children they want. If you plan to do polygenic embryo selection, 2 to 5 is a better estimate. If you want more precise numbers, use Heresite's calculator to estimate how many kids you could get from a given number of egg freezing cycles.
If you want to do polygenic embryo selection, aim to have enough eggs for greater than 2x the number of children you actually want. If you're interested in freezing your eggs or you're interested in polygenic embryo selection, send me an email. I'm happy to chat with anyone interested in this process and may be able to add you to some group chats with other women going through the process.
Subheading. Risks of egg freezing. Apart from the financial costs of egg freezing, there are some rare serious medical complications from the process and some common side effects from the process. Most women experience some level of bloating, abdominal pain, and mood changes as a result of the medications used to stimulate egg production.
In about 0.35% of cycles between 2001 and 2011, these side effects were serious enough to lead to hospitalization. The rate of hospitalizations has probably dropped by more than 50% since then.
There are things you can do to reduce the odds of serious complications like taking K-Bergolin after retrieval, monitoring your estrogen levels, and taking letrozole if they get too high, doing a lupron-only trigger shot, a few others. You can ask your IVF doctor or Claude about this stuff if you're curious. Bottom line.
Unless you're literally underage, sooner is almost always better when it comes to egg freezing. If you're one of the few women who visits this site, consider freezing eggs sooner rather than later. This article was narrated by Type 3 Audio for Less Wrong. It was published on February 8, 2026. Images are included in the podcast episode description.
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