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Understanding Fertility: Hormones, Age, and Differences Between Men and Women

Fertility is an important aspect of life, but it is often taken for granted until the time comes when a person wants to have a child. However, understanding fertility is crucial for both men and women, as it can help them plan for the future and take steps to improve their chances of conception. In this interview with James Nicopoullos, the clinical director of the Lister Fertility Clinic, we explore the connection between hormones and fertility, when a person's fertility starts, peaks, and declines, and the differences between men and women's fertility.

To hear Dr James answer the below questions in a video, click here.

1. Dr James, can you tell us about yourself and your work in fertility?

My name is James Nicopoullos. I'm the clinical director of the Lister Fertility Clinic and I'm also the person responsible, which is a regulatory title that means I have to make sure we comply with all the facility regulation from the hfpa, our regulatory body. I've worked at the Lister for around 14 years now, clinical director for about five. We've been an established IVF unit, within the Lister hospital for around 35 years now. I'm incredibly proud of the fact that, in a very difficult time for all of us at the height of the COVID pandemic in 2020, we hit our 20,000th baby that's been delivered through our treatments. So I'm incredibly proud of that, and still going strong, thankfully.

2. What is the connection between hormones and fertility?

This is a question that I could spend about an hour talking about. So it's really hard to condense. But in essence, there's lots of hormones that can affect fertility like your thyroid, which isn't a fertility hormone, but it can impact on things like miscarriage rate, for example. So it's important that they're tested and normal. The most important hormones from a fertility perspective is a hormone called FSH, follicle stimulating hormone. And as the name suggests, that's the hormone that your brain produces to stimulate your follicles and your eggs to grow. So what we want when we test something like FSH is it for it to be nice and low, because it suggests your brain isn't having to work too hard to make the eggs grow every month. As your egg number goes down, your brain has to work harder to make the eggs grow. In essence, it puts his foot on the gas so the FSH hormone goes up. So a really good marker of egg number, well, historically a really good marker. We know now it varies a lot from month to month, and within a month. So we've got a much better hormone now called AMH, anti mullerian hormone. And that's a hormone produced directly by the little follicles with eggs in them you've got in your ovary every month. So the more eggs you've got left in your stores, the more follicles there are growing every month, the more AMH hormone you produce. So it's a really good stock check of your egg number. And as a stock check of your egg number, there can't be a one size fits all because a 20 year old has got more eggs and a 50 year old. So it's really important when we check this AMH hormone and that we compare you for where you are for your age.

We talk a lot about polycystic ovaries. All a polycystic ovary is, is an ovary with lots of follicles, lots of eggs in it, which in essence is a good thing. But sometimes these women they produce the perfect amount of hormone to make the eggs grow, but the ovary doesn't respond quite as well as it should. So actually, when you've got polycystic ovarian syndrome, it means you've got lots of eggs, but your ovaries aren't quite responded to the hormones properly. But it's something that we can very easily get around if you're trying to get pregnant.

3. When does a woman's fertility start, peak and decline?

We spend a lot of our time worrying about how not to get pregnant throughout our life. So what we don't spend so much time looking at is actually when a woman's fertility begins to decline and how we combat that and when that happens. And in essence, if you look at lots of studies, a woman's fertility is a relatively flat line until her mid 30s. Then it goes down more slowly between 35 and 37. And then unfortunately, it goes down much, much quicker. And we can see that because the markers of egg reserve basically do that. Your success rate from trying to get pregnant naturally, perhaps is around 80% in the year at 30. Then drops a little bit to 70% at the year 35. And then drops much quicker to around 40% at 40. And it's the same with IVF, success is a relatively flat line at 35 and then goes down slowly and then much quicker there after. So really the younger woman is, the more eggs she has, the better the quality the eggs are. But it really only begins to decline from mid 30s onwards.

4. What about men's fertility - how does it differ?

Historically, we always talk about men's fertility not being impacted by age the way a woman's is. And to a certain extent, that's true, because men carry on producing sperm pretty much unchanged throughout their lives. Whereas unfortunately, women are born with and it goes down with age, which is why the quantity goes down, perhaps the quality goes down as well. In contrast, the production is pretty much unchanged in men. But what we do now know is, as men perhaps get beyond their 40s, the genetic integrity of the sperm, not so much the number of chromosomes and sperm, but actually the way the genetic material is packaged in sperm, can decline. And we do see that that can have an impact negatively in terms of chances of getting pregnant with partners naturally. So it's not quite as cut and dry as we once thought.

5. We know that a majority of people can't afford to freeze their eggs - but understanding your hormones is a more affordable and preventative solution - what can women do now to find out more about their fertility and hormones?

I think there's a couple of great tests that women should think about having when they want to assess their fertility. As I said earlier, the best marker we've got of egg reserve, from a blood test point of view, is AMH. And I'll come back to that in a sec. And the other good marker is by scanning you because the more eggs you've got in your stores, the more recruited every month ready to grow in response to your hormones. So if we scan somebody and do something called an antral follicle count, so count how many of those little follicles with eggs you've got there, it gives us an idea of what you've got left. Because the more we can see on scan, the more you've probably got left in your stores. And equally, that hormone, AMH, is a hormone produced by those follicles. So again, the more you've got left, the more follicles are there, the more AMHs churned out. So those two tests, that scan and that blood test, really help women understand what her egg number is like compared to where she should be for her age. And that won't necessarily change your chances of getting pregnant naturally, because if you've got a regular cycle, we produce one egg a month. But what it will tell you is how does your fertility compare to where you should be for your age? How long have you got before your fertility declines? What are your chances of success if you do egg freeze and need IVF? So it tells you how quickly you may need to do things.

6. For those who want to freeze their eggs - let's talk about the options and process.

In any given cycle, you've got a number of follicles there ready to grow. Naturally, one begins to grow. Eventually, the rest literally wither away and die after you release the one. What we're doing in an egg freezing cycle or an IVF cycle is trying to make as many of those follicles grow as possible. So we're giving you the hormone you produce naturally, that FSH hormone, at high doses, the only way we can do that is by daily injection. So during an egg freezing cycle, you have two weeks of injections to make the eggs grow, with four or five scans over those two weeks before you come in for that minor surgical procedure at the end of it to collect the eggs. So the whole thing takes about two weeks. It's really important to remember that we're not drawing any more eggs out of your stores, we're just using what would have come and gone anyway. So you're not suddenly going through the menopause early if you do this. It's really important to get those tests done, the AMH and the follicle count, in advance just to help decide, is it something you really need to do now? Is it something you need to do quickly? Actually, are your results really low and perhaps most important things to think about getting pregnant quickly. So it's not going to be right for everybody. We really need to get the information that we can from those tests, look at everybody's individual social situation and age, and then make some decisions as to what the right way forward is.

7. What are some practical tips for everyone to look after their hormones and fertility?

One of the main questions I get when I see somebody for egg freezing or trying to get pregnant is what supplements can I take? What lifestyle changes can I make? And the honest truth is, I think the most important thing is number one, people don't beat themselves up about that one cup of coffee or that one glass of wine that they take because the most important thing is people need to not smoke because that can impact on the quality of the eggs, genetics of the eggs, age and menopause. Nobody has shown that the occasional glass of wine massively impacts on IVF outcome, a lot of studies suggest it doesn't. And I think the real important thing, is not to be stressed about stress. Because you know, fertility problems can cause stress, other life events at the same time are stressful, it's not going to impact, from the best studies that we have, on the outcome of an IVF cycle or an egg freezing cycle. And it's important, as I say, people don't beat themselves up. Most things in moderation, exercise is fine. I think the key is to avoid smoking, and to moderate most other things.

8. How long should women try and conceive before seeing a doctor?

The question as to how long somebody should try before they come and see someone like me is a really good one. And there's no right or wrong answer. Because what I always like to talk about to somebody, when they come and see me is, what are my chances naturally, because it's worth knowing that to make sure Plan B and Plan C are worth doing. If you're sitting in front of me at 30, for example, and you've been trying for six months, and everything, all your tests are normal, then actually, even if you carry on trying for another year, year and a half, two years, even, the success rate of IVF isn't going to be significantly lower at 32, compared to 30. In contrast, if you're sitting in front of me at 43, and you've been trying for six months, then actually, you know, delaying things any longer may significantly decrease the success rate of IVF below what it already is. So I would probably say anybody who is not pregnant within a year should be seeing somebody just to make sure the sperm counts okay and the tubes aren't blocked. And thereafter, how quickly proceed with treatment really depends on how old you are. And perhaps over 40 it might be worth seeing somebody slightly earlier than that, if you haven't conceived naturally, as the need to act quicker, is perhaps more important then.


LIVE conversation: How to understand and optimize your hormone balance and fertility

Earlier this month we hosted a LIVE event with Edwina Dunn, The Female Lead's Founder, and Yasmin Baba, Co-Founder and Chief Product Officer of Amilis. Unfortunately, Dr James Nicopoullos could not join the call due to a bad internet connection. Watch the conversation below.

To find out more information about hormones and fertility, see our Health Pillar page here, download Dr James' PDF below and visit the Amilis website.

Fertility PDF
Download PPTX • 380KB


More information about this contributor:

Mr James Nicopoullos is a sub-specialist in Reproductive Medicine and Surgery and a Consultant Gynaecologist at HCA Healthcare at The Lister Hospital.

He has a wide range of experience with IVF and subfertility but also welcomes those patients that suffer from reoccurring miscarriages, menstrual disorders or those approaching or going through menopause. James is a talented physician and an accredited laparoscopic and hysteroscopic surgeon, offering clients a one-stop shop for diagnosis and treatment.


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