Knocked Up Podcast - Why the Media Doesn't Get Egg Freezing
With elective egg freezing being so new, how we interpret the data in the context of today's population doesn't quite give the accurate story. Dr Raelia Lew explains.
With elective egg freezing being so new, how we interpret the data in the context of today's population doesn't quite give the accurate story. Dr Raelia Lew explains.
We recommend listening to the 'Beyond Expectations' podcast episode "Kate Lancaster on What They Don't Tell You About Egg Freezing"
TRANSCRIPT
JORDI MORRISON: Hello and welcome to Knocked Up, the podcast about fertility and women's health. You are joined as always by me, Jordi Morrison, and Dr. Raelia Lew, CREI fertility specialist. Welcome, Raelia.
DR. RAELIA LEW: Hi, Jordi.
JORDI MORRISON: The title of today's episode is Why the Media Doesn't Get Egg Freezing. What's brought this on?
DR. RAELIA LEW: Well, I noticed that over the Easter long weekend, there was a really... big article in The Age newspaper. I'm not sure, it might have been in other associated — Good Weekend, so Sydney Morning Herald, probably other associated press around Australia. And I was reading that article and it just occurred to me that despite the journalists getting different perspectives from many different people in fertility fields, fertility specialists from various units, academic. Also, I think they were quoting some scientists. They just don't get egg freezing. And I thought maybe we should talk to our listeners about it and give some perspective.
JORDI MORRISON: I think it's a great idea. I've also read the article because you sent it to me. And yes, I guess a few things leaped out to me too about this article. And interestingly... this week, I listened to a podcast about egg freezing, and we'll link to it in the show notes. It's from someone who was a patient of yours, which she does mention in the podcast. Her name's Kate Lancaster, and she's a journalist, and this podcast was actually about her experience freezing her eggs. We love Kate. This is in no way biased, but it's a very good episode to listen to if freezing your eggs is something you're thinking about. In the article, Raelia... They mentioned some results, and I'm just going to throw them to you, and then I have a question. And it's that they reviewed 9,000 women, 11% returned to use their eggs. Of this 11%, only 28% gave birth to a live baby. And they go on to talk about Jennifer Aniston and how the technology has evolved. And so that makes me think, Raelia, in the loveliest way, you've now been doing this for a relatively long time, especially considering the age of this technology. How have you seen this space evolve in that time?
DR. RAELIA LEW: So it's evolved a lot and I've also been doing this in private practice, which is really where most egg freezing happens, for over a decade now. And I think that a lot of studies that journalists read and quote actually don't compute in the modern world. And I think to put that into perspective really, egg freezing is what, 15 years old?
JORDI MORRISON: No, it's actually more like 30 years old.
DR. RAELIA LEW: But we've only been good at it in the era of vitrification and that started in about 2012. So look, why studies and journalists get it wrong is that research takes time to do and follow-up periods are limited in what is published, and the data of women who freeze their eggs has changed fundamentally and radically in the time that people have been looking. So when I first started egg freezing... was really a technology that was used only for women who had cancer as an experimental offering so that they could freeze eggs and then have chemotherapy, because we do know that cancer treatments often do unfortunately have the unintended consequences of causing menopause through the chemotherapy killing eggs in the ovary. And so a lot of women who do have serious cancers and need rounds of chemotherapy can ultimately go into premature ovarian insufficiency, and having frozen some eggs or embryos before their treatment may allow them to have children after their remission and recovery. So they were the main group of women who froze eggs initially. We then had a situation for many years where egg freezing still had that experimental label and it was starting to be offered electively, and people who decided to use it were actually at the tail end of their fertility, so they were already in the infertility zone. So I would, when I started my career, see mostly women in their late 30s and even early 40s wanting to freeze their eggs. And that is something that really affects return rates because if you're freezing eggs at that age, firstly, the eggs you freeze are not as good. And so if you do return, you're less likely to have success. But also, you're probably closer. Not quite at that point, which is why you freeze eggs in the first place, but you're closer to coming to terms with the fact that you may not have a child yourself with your own eggs. And a lot of women who did freeze their eggs in that demographic and did not return decided not to have children. The demographic of women freezing eggs today is very different and it's changed a lot over the course of that time. So, you know, when I started in around... 2015 in my private practice I would still say the average age of women freezing their eggs was about 37, 38, and then probably five years later it went down to more like 36, 35, and now I'm seeing more women actually freeze eggs at the right age, which is in their early 30s, and occasionally younger if they have serious gynecological concerns and reasons to do it, so like women who have serious endometriosis and they know their fertility is going to be compromised. Or women who might have premature ovarian insufficiency or family history of early menopause might choose to freeze eggs even younger. But the majority of women who I see freezing eggs now are in their early to mid-30s, which is great.
So why the media often gets it wrong when they quote stats, and why I think the stats that they are quoting are wrong, in terms that they're not wrong as in they're not interpreting data wrong or reporting falsely, but they're just making the false assumption that past demographics when they analyze data from 10 years ago reflect today's population, and they just don't. It's different populations and their success rates are different and their return rates are different. I also can tell you from my personal experience as a fertility specialist who has been a big advocate and champion of egg freezing for women, that I've had a large and increasing number of women return to use their eggs. And in my own personal anecdotal experience, the majority, the vast majority of women who have come back to use their eggs have had a baby under my care. And I have a growing number of frozen egg babies in my practice. And it's amazing. And I've really seen this science transform lives. There have been some women who've come back and they've had their eggs fail. I've had a few of those cases, only a handful. So I really think that the stats that are looked at, particularly in international studies as well, don't reflect our population of women who are freezing eggs.
Now, it's a paradox with egg freezing. The younger you are when you freeze eggs, the less likely you are to return to use them quickly because you have... significant amount of potential natural fertility time ahead of you, and if you're not infertile, a significant proportion of women may conceive naturally and achieve their goals without using their eggs. Now I have a patient who's just returned to my care who I froze eggs for getting close to 10 years ago and she's had two children naturally. She was single when she came to freeze her eggs and didn't have a partner. She then coupled and had babies. And now in her mid-40s, when she would like to have a third child, she's going to use her eggs. It's one of those things that people have this idea of who's going to freeze their eggs. They think, oh, it's this career woman. She doesn't want to have children. She's not committed to a relationship. She's just trying to have it all. understand that we are complex in our reproductive relationships, things are not simple, we care about who we have babies with, we care about the context, if we're going to have children alone we want to be financially secure, we want to have the ability to raise a child in the manner in which we choose, and having frozen eggs gives women options and gives women advantages and gives women choices. And it's one of those things that they don't always decide to use them, but I can tell you that quoting in The Age newspaper that 28% of women who use their eggs have a baby — in my personal experience, in my practice, in the labs that I've worked in, that is just not true.
And so what I think, and the reason that I think they're quoting these data, is they don't understand that past demographics and past... patterns of use that they can report and publish do not reflect current practice, and they also don't understand that women generally take five to ten years to come back to use their eggs. So the women who froze their eggs in 2015 were starting to see their outcomes in the next couple of years, and in a few years later we'll be able to report on those. And I would put it to you that women who froze eggs before that do not reflect current users and do not reflect current benefits. So my prediction is that we will see more and more babies coming from frozen eggs and we will see more and more women having the opportunity to have the families they want over time, and that we need 20 years of data before we can really make those comments. And I do think education is important, and there are a lot of other issues covered in that article that you might want to talk about. But the reality is that we need to look at the changing context and demographics around egg freezing, and we also have to pay homage to the incredible work of scientists in advancing the utility of the technology. That if you freeze healthy young eggs, they will come out of the freezer behaving like healthy young eggs. And you will, at 40, be able to have the fertility you had at 30 from those eggs.
Now, I always say to my patients, the only absolute guarantee you can have a baby is to have a baby. And when we put assets in the freezer for the future, they have not yet translated into an outcome. And there's no doctor who can look at you and say, if you freeze 20 eggs, you'll definitely give birth. We don't know, there's too many uncertainties in the future. An example is if you come back with a partner who has terrific sperm health, you're going to do better with the same eggs than if you come back with a partner who has seriously compromised male factor issues. Things are complicated and it's not just about the egg. But on principle, if you freeze a lot of eggs and you freeze a good number, and remember that you release 12 eggs naturally in a year of ovulating, so if you freeze 20 eggs, it's like two years of ovulations in the freezer. Hey, most 30-year-old women who try naturally for two years have a baby. You know, we all know that there'll be some people who don't and who do need extensive fertility help and assistance because they have serious problems. But most women who freeze eggs for the future as an elective concern do not have infertility and their chances of having a baby with those eggs are terrific.
JORDI MORRISON: There's a couple of points I want to pick up on there, Raelia. Firstly, you talk about age and kind of early 30s being optimal. Are you finding, because there's a lot of chat about egg freezing in the media, especially on social media, that even younger people are coming to see you? And what is your advice to them?
DR. RAELIA LEW: Yeah, I actually spoke to a journalist who wanted to interview me for an article about this because she was concerned — if there was, this was a different article, it was about Medicare and whether Medicare could help with egg freezing because currently it doesn't for people who don't have an underlying infertility issue, and I actually believe that it should — but the concern was raised, well, wouldn't just people at 21 or rush and freeze their eggs and they never actually needed to. And I would say absolutely not. So look, egg freezing is something that women think about when they're thinking about reproductive health and future fertility, and I put it to you that most 21-year-old women are not thinking about that. You know, it's just not on their on their agenda at that time point, and nor should it be. Well, you know, our grandmother's generation it probably was and they were probably all having babies around that age and you could argue that actually that's when we're actually very fertile, but your society's changed and the way that education works and career works and expectations. But cost of living, few 21-year-olds would be able to afford egg freezing. It is still a significant out-of-pocket cost the way that it currently is structured, and it's something that women think about when they're contemplating their fertility and they're thinking about investing in their future. And there's many ways that we invest in ourselves and in our future, and I would say that as females we should know and we should be educated to the fact that fertility options do diminish with age, and it's definitely our prerogative to consider that. And I certainly think that women shouldn't be lectured to as to how they spend their money. They shouldn't be fear-mongered into egg freezing either. But if someone's proactive and they want to create a resource to give them a better chance later in life to have the family they want on their terms, then I am fully supportive of that. And, you know, the cost of egg freezing has come down substantially. It is what I would say an affordable thing for women to do in many circumstances. And I fully respect that not every woman's going to be able to afford private health care. They're not going to be able to afford to freeze their eggs and that it's still out of reach for many people. And I certainly do understand that and don't want to be dismissive of that. For those who can afford it, it's a relevant choice and and I certainly think that it should be on the spectrum of things that women think about and consider.
JORDI MORRISON: It's a lifestyle choice isn't it, so it's like you're deciding, do I go on that holiday, do I buy that designer handbag, do I freeze my eggs. It's something that you consider, it's something that you consider in the realm of self investment and self-care.
JORDI MORRISON: Thinking about the number of eggs you need to freeze, it's mentioned in the article and also you've mentioned it there too about 20 eggs. Why is 20 eggs considered to be the number?
DR. RAELIA LEW: There's no absolute number that's going to guarantee a baby, but statistically, and remembering that statistics are based on outcomes that we have in the lab, you're going to have a more than 90% probability of at least one live birth if we have 20 eggs to work with. And we take into account that not every egg is going to survive the freezing and warming process. Not every egg is going to fertilize correctly. Not every embryo is going to make a quality embryo that we would either transfer or freeze. We take that into account. And a blastocyst embryo in IVF, depending on the age of the egg, will have somewhere between a 50% probability of live birth and a 5% probability of live birth, depending on the age you were when you made the embryo. So if you're kind of in your 20s, you're going to have up until around the age of 30, about a 50% probability of live birth per embryo transfer. Whereas when you're between 30 to 35, it's going to go down 40%, then 30%. When you're 40, it's going to be more like 10% to 5%, depending on the quality of the embryos.
It's one of those things that the age of the egg is the most important factor. Just to point out what might be obvious to some but some might not quite understand, if you are 40 and you have an embryo transfer from an egg that you froze when you were 30, then that embryo is going to have the chance of making a baby that you had when you were 30. So you go from an embryo having about a 5 to 10% chance of turning into a baby to that embryo having, depending on your age, maybe a 30 to 40% chance or even a 50% chance of becoming a baby, depending on how young you were when you froze your eggs. So if you froze your eggs at kind of 30 it's going to be more like 50-50, and if you froze your eggs at 35 it's going to be more like 30 to 40%, but still radically different. And so what that means is if you have a few embryos you're highly likely to have a birth, and you might get pregnant with your first, you might get pregnant with your second or third embryo transfer, but you're highly likely to succeed cumulatively. That's where the number comes from.
Now we at Melbourne IVF have invested a lot in the technology around egg freezing and we continue to do so, and there's research developments that we're looking at as to how we can apply things like artificial intelligence to analyse the eggs that we have before we freeze them, and that we'll be able to in the future, we hope, personalise advice for individuals so that we won't have to counsel on average. So probably it would still be that most women were advised to freeze a similar number of eggs, but we might be able to say to someone whose egg quality was poor that we were able to analyse that with more information, that they should freeze more eggs, and so we'll be able to personalise prognostication to the individual so that we can improve still even further the chance that someone will have success when they come back to use their frozen eggs.
JORDI MORRISON: We always talk about women freezing their eggs but we don't talk about men freezing their sperm. I'm sure we've answered this indirectly in many previous episodes. But a quick recap, Raelia. Why is the focus on eggs, not sperm?
DR. RAELIA LEW: It's a good question. And the answer might surprise you. I would say actually it's reasonable for young men to freeze their sperm if they want to. Because as we get older, sperm actually accrues DNA damage too. And we know that... woman is 40 and she's trying naturally with a partner who's 25 versus trying naturally with a partner who's 40, she's going to get pregnant more easily with her 25-year-old partner than she is with her 40-year-old partner. And that's because the egg is a very important cell, but it also has all the DNA correction mechanisms when it comes to the embryo. And so if you give an egg that is more compromised because it is older, it's been waiting longer, easy sperm to deal with, then she's going to be more successful in making a healthy embryo than if you give her compromised age sperm. Now the other way around works too. So if you have an older man whose sperm has some DNA damage and he has a baby with a younger woman who has healthy young eggs, so you kind of Mick Jagger scenario, then her eggs can compensate for his age-affected sperm and correct DNA errors in the DNA given from the paternal side that inevitably come with aging.
We do know also from data that men who are over 45 certainly have an increased risk of say fathering a child with things like autism and complex. Not single gene problems, but what we call epigenetic problems. They have an increased risk of having de novo single gene mutations in the offspring that didn't come from either parent, but was paternal error derived. So things like achondroplasia, which is dwarfism. Or things like schizophrenia, more common in older dads. There is actually an argument from a biological perspective for men to freeze their sperm. But I would say just like women at 21 are not thinking about freezing their eggs, I would say probably men at younger ages are not thinking about freezing their sperm, even though it's much cheaper for them to do it than it is for women to freeze their eggs. And so much less invasive.
JORDI MORRISON: Yeah. Exactly. It's easier and cheaper and maybe they should be freezing their sperm. I mean, we're learning when we look at data, we're learning that men who are trying to have babies are becoming less fertile around the world. And there were some quite interesting studies published on that and sperm health and count and motility and things like that declining with time, and fingers were pointed at things like endocrine disrupting chemicals in our environment. But, you know, the pink elephant in the room is age and we're trying to have babies a bit later in life on the female and male side of things, and that does have some potential implications.
DR. RAELIA LEW: The other thing to say about why women talk about freezing their eggs and why men don't talk about freezing their sperm, aside from those factors we've just discussed, is that biology of the sperm and the egg is completely different. Men start making sperm at puberty and they keep making sperm until death. They don't stop. And they make new sperm from the stem cells. So while the quality of that sperm is age affected, they still make new sperm and it is still potentially viable. Women make our eggs in utero. So when we're a fetus, we've made all our eggs. You know, I often say to patients, you know, if you're at a 20-week ultrasound looking at your baby and it's a female baby, she's made all her eggs already. And so those eggs, they have a different biology and they're kind of in a vault in the ovary. They're stored and they're released gradually. And they're released up until menopause. And we lose our fertility about 10 years before we lose our periods because egg quality gets to a point where the eggs are off, for want of a better word. They no longer have biological potential. And that's because they're metabolically fatigued and they start making cell errors very frequently.
And the egg has serious heavy lifting to do when it comes to making a baby. An egg is about 150 microns in size, and the embryo, once it's fertilized, actually stays that size for at least a week of development before it hatches out of its eggshell. And the egg supplies 99% of the ingredients of the embryo, minus the male DNA. Certainly all the cytoplasm, which is the cellular machinery, all of the, I guess, metabolic factors, the energy that the cells need to make the embryo. And so when that egg is tired it trips up and it's got a lot of complex things that it needs to do, including making sure the embryo has the right amount of DNA and the right balance, but also just ensuring that all the cellular processes involved in making all the organ systems in the body go correctly. And we just know that eggs have a use by date and that is really the biggest barrier to female fertility.
It's not the only barrier. We do, as we get older, accrue pathologies. Nobody's born with terrible endometriosis. Nobody's born with fibroids or adenomyosis. Our cycles themselves become dysfunctional as we get older because our hormones are not as balanced as they should be, as our cycles shorten with age and as our ovarian reserve declines. But other things being equal, if a woman has a normal uterus, she can get pregnant with an egg that has potential even beyond her menopause with hormonal support. It really does come down to the age of the egg, not the age of the mother, and the biological potential of the egg.
And that's where egg freezing, it shouldn't be oversold. And I'm 100% not in favor of saying, I'll just freeze your eggs and you'll be right. I mean, you still do need to plan and make sure that you're healthy. And I would say the earliest age in life that you're ready to have a baby is your best chance of having one. But I also think it shouldn't be undersold. It's a miracle of modern science. And I think that it's actually false to say that we have seen what it can do. We haven't. It's just early days. In 10 years from now, I think we'll be able to look back on egg freezing and say, this is what it can do. Until then, we don't have the data to show us its potential. And my opinion is that looking retrospectively, we undersell the technology. We don't oversell it.
JORDI MORRISON: Thank you, Raelia.
DR. RAELIA LEW: Thanks, Jordi.
Hosted by Dr Raelia Lew and Jordi Morrison
Dr Raelia Lew is a RANZCOG Board Certified CREI Fertility specialist, Gynaecologist and the Director of Women’s Health Melbourne.
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