Time To Discuss The New WHO Sperm Guidelines (Episode 637)

Lisa Hendrickson-Jack:

This is the Fertility Friday Podcast, episode number 637.

In today’s episode, we will be talking about the updated sperm guidelines, the updated WHO, World Health Organization, guidelines they released in 2021. This is the first major update, if you want to call it that, since the 2010 guidelines were established. In today’s episode, we’re actually going to go through and talk about what they did, what they changed, what was improved, and essentially where we’re at now.

You’ll find the links to the papers referenced in today’s episode on the show notes page. You can head over to fertilityfriday.com — this is episode number 637 — and you’ll be able to find it from there. You can also find it from your podcast player if you’re listening in there. There’ll be links in there as well.

The main paper that we’re looking at today is a critical review of the most recent update of the WHO’s guideline for semen analysis. This is the test that is used widely worldwide. If you are working with clients who have had these tests done, that is a criteria used to evaluate semen analysis. And if you yourself are trying to conceive and your partner has had a semen analysis, this is the established framework from which they will evaluate those tests.

We’re going to go through what stood out the most to me. We’re going to go through what changed with the guidelines. We’re going to go through how they established the changes that they made and just kind of talk about it, because I’m always very interested and curious about how these types of situations come about.

What I found is the more that I talk about how these criteria have been established, people really just don’t know. They have no idea how the criteria has been established. A little bit of background — just to put it out there, for those of you who already have Real Food for Fertility, we have an entire sperm chapter that delves into this information in a ton of detail. You’ll find more information in there if you’re wanting to take a deeper dive.

I think it’s helpful just to know that the World Health Organization has now published six different editions of its semen analysis manual since its first in 1980. There have been updates in 1980, 87, 92, 99, 2010, and now 2021. In Real Food for Fertility we actually placed a table in there so you could see the changes up to 2010.

Across these different editions, what you see is a trend towards a lower bar that is used essentially to evaluate semen analysis. We see a drop in the minimum sperm concentration. We see a drop in the morphology number. We see drops in the motility number. Over time, we’ve seen them really lower the bar as to what is considered quote unquote normal for a semen analysis.

The 2010 edition was the first edition to use an actual data set from fertile men. In case you don’t know how this initial 2010 guideline was set, they did a study. There were about 19,000 men, just under 2,000 men who were partnered, and they were looking at couples who were trying to conceive. Out of the couples that were trying to conceive, they ended up with a population of just under 2,000 men whose partners had conceived within 12 months of trying.

If you picture this scenario, they have the sample of couples, and out of the sample, they looked at all of the couples who conceived within a 12-month period of time — from the time that they started trying. This is their pool that they were using to develop these criteria. Just under about 2,000 men from eight different countries. All these men are technically fertile because their partners did conceive within a 12-month span.

In case you didn’t know how they determined the criteria, the WHO criteria, they divided these men into centiles. They looked at the different percentiles. Just think back to your, whether it’s high school or university days, when you are dividing things up into centiles.

In order to establish the guidelines, they actually looked at the lower fifth centile of this whole group of men. Out of this group of just under 2,000 men whose partners had conceived in a year, they tested their semen and stratified the semen analysis on a scale. They looked at from the lower centile to the higher, like 97.5%. They didn’t go with the middle ground. There’s a variety of different ways they could have analyzed this data. They used the lower fifth centile of this group of men to base the WHO guidelines on.

That does mean that 95% of the men in the study had better sperm than the guidelines that they’re using. When they initially made this change in 2010, there were some fairly significant drops, and there was some debate. If you look at the research that was coming out around that time, there were concerns because when they continued to drop this criteria, it’s estimated that about 15% of the men who had at least one abnormal parameter under the old criteria — between 1999 and 2010, based on the 1999 criteria — about 15% of the men would have been classified as abnormal. They would have been screened, they would have been analyzed, assessed. But when they initially dropped these guidelines in 2010, that 15% of men is automatically classed as normal. There was some debate on that.

I think the takeaway from this kind of initial discussion around how they develop these parameters is that they are not developing these parameters based on what would be considered optimal. That would be the biggest takeaway. This is what we always talk about with our practitioners and what our practitioners talk about with their clients. The parameter that they’re using — I just told you how they established it. They didn’t look at what would be optimal.

They looked at the time to pregnancy over 12 months. All of these men, their partners conceive within a year, but they didn’t ever provide a table that shows who conceived within the first month, or the second month, or the third month. It leaves questions that we don’t have answers to. This lower fifth centile — on average, how many months did it take this couple to conceive if the partner’s semen analysis was in that low fifth percentile? This would be interesting and important information for couples who are trying to conceive or for practitioners who are trying to support their clients, but that information is not available publicly.

The second thing that stood out to me with this update is how they did it. You might think to yourself, okay, well, if after 11 years — from 2010 to 2021 — they’ve now created new guidelines, you would think that maybe they did a new study. You would think maybe they did the research in a different way. But that’s not exactly what they did.

What they did in order to determine these new numbers is they actually kept the initial data set of men — that initial data set that was just under 2,000 men. They kept that, and what they did was they added in data from other research studies that were already conducted of men whose partners conceived within 12 months.

They ended up with a total data set of about 3,500 men from 12 countries on five continents. They had the original data set that was just under 2,000, and they added just under 1,800 to that — again, from other research papers that had already been done. They brought this data together, and from that data, they did the same thing that they did in 2010. They put it all together, and they divided it by centiles, and they used the lower fifth centile again.

With this, you could call it a new data set, but really only 50% of the data set is new. They added back in the old data set. As you can imagine, if you’re following what I’m saying, they came up with now, quote, new numbers, but half roughly of the participants were the same ones in the initial 2010 study. They didn’t conduct a new study. They just did samplings from established research that provided similar data. They added just under 1,800 new participants to the old numbers, ending up with a total of about 3,500 men, half of which are the same as before. From that data set, they now have, quote, updated the data.

I find that to be really interesting. Basically, the outcome of doing it this way is that these new 2021 semen analysis parameters are not that different from the 2010. It kind of begs the question as to why even update it if it’s barely any different.

For example, the semen volume was previously considered to be normal — I’m going to go through, based on the WHO parameters, comparing the 2010 with the 2021, and talk about what they are officially considering as normal and how it changed. The 2010 data, normal semen volume was considered to be 1.5 milliliters — again, this is the lower fifth centile. The 2021 data, 1.4. Oh my goodness, so glad they changed that, so different.

The total sperm number didn’t change — 39 million total sample didn’t change. The total motility changed from 40% to 42%. Again, not that different. The progressive motility — what they would consider to be normal — changed from 32% to 30%. So the progressive motility, meaning the sperm that didn’t just move but moved forward, went down to 30%. The morphology stayed the same at 4%, meaning out of every 100 sperm, 4% are normal visually. And the vitality number, that would be the percentage of sperm that are actually alive versus those that are dead, lowered from 58% to 54%.

The overall takeaway — I know I’m throwing numbers at you here — but if you look at the 2010 versus the 2021, there’s not really much difference. If you think about how they did the study, how they took basically the same men from the first 2010 study and added about the same number of participants, of course it didn’t change very much. That is really interesting, but all of this kind of ado and the numbers don’t really change. If anything, I would say the change is more nominal. They did it the same way — they just added to their data set so they had a larger number of men and continued to use the lower fifth centile.

One thing that was different, that kind of stood out, is that in this new updated WHO guideline for semen analysis, they did include some information about sperm DNA fragmentation. You could also refer to that as sperm DNA damage. They did add this to the manual. They had a discussion of its relevance — it said it could represent an important addition to the workup of male infertility, becoming one of the most discussed and promising biomarkers in basic and clinical andrology. It also acknowledged that sperm DNA fragmentation is prevalent among men with abnormal ejaculate parameters.

There’s a lot of research coming out about the role of sperm DNA damage. In next week’s episode, I’m going to be sharing a paper that really looks at that and its relation to miscarriage. If this topic is of interest to you, then you’ll appreciate next week’s episode as well.

What’s interesting about it is that in their new document, they talk about it, but they didn’t really provide specifics for clinicians. They didn’t provide specific thresholds or specific clinical indications as to when this testing should be requested or when this testing should be done. They didn’t provide a specific framework for how to use these results in practice. While they did include it, and that’s different and important that they did include it, they didn’t necessarily include very specific guidelines for that.

That begs the question of how is this going to change the way that patients are treated in the average setting. They simply talk about it, but don’t necessarily provide a lot of details on it.

This is one of the reasons why I wanted to just today go through some of these changes. In a short podcast episode, I can’t possibly go through every possible change, but I’m just kind of highlighting some of the main points. I wanted to establish that there has been this trend over many years, over their six editions, downward trend.

It’s interesting because that could simply be mirroring the issue that we’re seeing broadly across the world, where there is a well-documented decline in semen parameters that has been going on for the past 50 to 70 years. The average man in the 40s had far better sperm parameters than the average man today. There are many reasons why that is happening, from changes in our diet and nutrition to changes in our toxin exposure and exposure to chemicals that have estrogenic effects. It’s a pretty big and significant conversation.

I think the last piece of this that really stood out to me was that after all these years — the first manual came out in 1980, and here we are, we are in 2026, but this newest guideline was updated in 2021 — the changes are fairly marginal to the data itself. They use the exact same standard for how they determined it. They simply broadened their group.

I think it’s really fascinating that they kept the original group and just added more men to it. It seemed like they didn’t really intend to make any sweeping changes. Maybe they’re content with the way that things are now. But there are a lot of questions that are not answered by this kind of standard parameter that they’ve created.

You would think that if you had these studies where they’re looking at men who are in relationships and whose partners are conceiving within 12 months, then there would also be a data set of men whose partners did not conceive within that time. Wouldn’t it be interesting and beneficial to specifically look at the semen parameters of couples where the men’s partners did not conceive within that 12-month span, technically falling into that clinical definition of infertility?

You look at the parameters of the men who conceived in that time, but wouldn’t it also be interesting to compare that to the parameters of the men whose partners did not conceive during that time? Wouldn’t it be interesting, as I mentioned earlier, to also look at the time to pregnancy breakdown — to look at if there was any difference between the average time to pregnancy of men in the 75th centile, the 50th centile, the 25th, and the 5th? They’re saying, okay, we’re going to use a lower fifth centile and that’s going to represent what’s normal. But what if men in that category are associated with a longer time to pregnancy? We just don’t have that information.

What’s interesting is that I was doing some research on this paper and the data set is publicly available — you can actually go and download it. But what’s interesting is that they did not divide that data. Even if you try to go to the source and get that publicly accessible data, the raw data that they use from the study, they do not include any time to pregnancy breakdown. We can’t know the answer as to whether the men in that lower fifth centile actually on average took longer to conceive.

To put this all together, what is my complaint here? My complaint is that these new guidelines that were updated in 2021 do not provide us with any additional information on the question of subfertility. It just provides us with, I would say, an arbitrary decision of how they’re going to determine normal. They are, I would say, looking at fertility differently to some of our brand practitioners who are trying to optimize fertility markers for natural conception.

When you’re trying to optimize fertility markers for natural conception, we’re not just going to go with this bar that seems kind of random. Why would you just look at all these men and choose the lower fifth centile? Why not choose even the lower 15th? Why not choose the lower 20? What is the rationale for choosing this?

I recently presented some information on sperm parameters to one of our FAM groups. All of them looked at me with this kind of curious look, and we talked about it. They were all kind of confused as to why would they do it this way. This is why I think it’s important to just break it down, to just talk about what they did and how they determined the information. Because when you actually look at it, it is very clear that these numbers were never meant to be optimal.

When we look at studies that are trying to determine what is optimal, they do look at the time to pregnancy. One study that I’ve cited in both The Fifth Vital Sign and Real Food for Fertility actually looked at not only the parameters in general, but they looked at how long it was taking couples to conceive. They looked at the question of, well, at what level do those sperm parameters start to have a negative impact on the time it takes to conceive? When the sperm parameters drop to a certain level, at what point does it now start to take these couples longer to conceive — more months versus the couples who are in more of an optimal range?

When you ask those kind of questions, you actually get very different numbers to the WHO numbers. Optimal concentration is considered to be closer to 50 million sperm per milliliter, when the WHO numbers are right there at 15 million per milliliter. When we look at what’s optimal in terms of motility, the motility number is closer to like 68% versus the 40 or now 42% motility. What that means is that out of every 100 sperm, according to the 2021 guidelines, 42 out of that 100 are actually moving. Does that mean that 58 are not moving? What are the implications of that?

If we look at what would be optimal for morphology, the WHO says 4%, but the optimal — when we’re looking at what point does the lower parameters start to have a negative impact on time to pregnancy — they are looking at an optimal number of about 12%.

Basically, what Lily and I are arguing for in Real Food for Fertility is just a recognition that there is a subfertile population of men, and that subfertile population of men exists between the WHO guidelines and these optimal guidelines. You could be trying to conceive, and your partner could have a semen analysis, and he could be told that he’s totally fine because he meets these guidelines. But if we’re looking to optimize the chances of natural conception, then we would really want to be looking at a more functional guideline that was designed to identify what’s optimal instead of simply pulling the lower fifth centile of a group of 3,500 men whose partners conceived within a year, without really knowing if the men in the lower centile actually had a longer time to pregnancy.

Of course, if I ran the world and if I was doing the study, that would be my hypothesis. My hypothesis would be that the men in the lower centiles would have a longer time to pregnancy. It would be then very helpful to actually do the study to see if that’s true, because we can’t just base things on our opinion. But these are the study questions that I would like to see looked at.

Now some of you may be wondering, well, why is it that they would use this method and strategy for creating these guidelines? I can speculate on this — it doesn’t mean that this is the reason — but when looking into it, when you’re making big decisions for numbers that are going to be used for public policy, one of their concerns is that they don’t want to put the numbers so high that they’re kind of collecting healthy people. They’re kind of intentionally putting those numbers lower so that they don’t end up over-diagnosing people. That is a possible explanation. It doesn’t mean I agree that that’s the best way to go, but I think it can help us to understand perhaps why they went this route. Because technically, if they’re looking at a fertile population, then by choosing that number, they’re kind of saying, well, all of these couples conceived. It makes sense in their brain anyways.

Like usual, I do think that it’s important for us to continue to be looking at what research is available and continuing this conversation about what is optimal. Like I said at the beginning, if you and your partner have been trying to conceive, I will continue to just stand on this hill and say that when you are trying to conceive, from a statistical standpoint, if you and your partner have been timing sex correctly and it’s been six months to a year or more of you trying with no success, and you are actually tracking your cycle and having sex at the correct time, then statistically speaking, men in those situations who have their partners — they’ve been trying for over a year with no success — statistically, they’re much more likely to have lower sperm parameters.

The takeaway here is that we always have to take it to the next step. We can’t just assume that if your partner has been told he’s fine, that that actually means that his semen is optimal. There’s a very strange tendency in our medical community to not look at the men or to overlook the men. Part of it is because of these very low WHO guidelines.

If you take a deep dive into the research, they already have their solution to male fertility challenges. In case you didn’t know, IVF procedures, artificial reproductive technology, ICSI procedures — all of these things that fall under the umbrella of artificial reproductive technology — those procedures are basically the medical solution to male infertility. When a man falls below those guidelines, yes, they may be evaluated, and yes, there’s research about a variety of different nutrients and things that can support. But generally speaking, the referral is to jump into artificial reproductive technology. That’s considered to be the solution to male infertility. There’s certainly a lot more conversations to be had, and I certainly think that this is an important place for us to land.

Whether you’re working with fertility clients or whether you are yourself trying to conceive, this is a very important conversation. We should not be overlooking the semen analysis. The good news in all of this is that if your partner’s parameters are low, there’s a lot of evidence-based strategies to improve and support sperm parameters, and there’s also a significant rationale to have him further assessed and analyzed. This is not always done, and it’s a very important conversation. Hopefully that is one of your main takeaways.

If this topic is of interest to you, then I would highly encourage you to read the sperm chapter in Real Food for Fertility. I really went ham on that chapter. There was a time when I wanted to write a whole book on sperm parameters. Because after years of working with fertility clients in the fertility awareness world, you have the ability to have some really deep insights into what’s happening in the menstrual cycle. You can support your clients to time sex correctly based on the cycle. You can confirm ovulation when it’s happening in the cycle. There are many couples who simply learn how to time sex correctly and conceive rather quickly, even after a while of trying without success.

But on the flip side, when you have couples that are trying to conceive and they’re timing sex correctly and they’re just hitting that window over and over and nothing is happening, we have to start asking about the sperm. It just makes logical sense. We have to start asking about the sperm. That’s essentially what this is all about.

With that said, I will wrap now. I think I’m beating it to a pulp at this point — I’m a broken record over here. I’ve been talking about the sperm conversation for many, many years. But I’m glad that I had the opportunity to dissect and discuss these changes, if we want to call them changes — these very minor changes that don’t necessarily move the bar very far. I think it is eye opening for clinicians and women alike.

If you can think of anyone who would benefit from hearing today’s episode, then please do share it, please do pass it along, because this is very important information. As always, until next time, be well and happy charting.