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In this episode of On Health, I dive deep into period myths, including the myth of the normal period, and the science and culture of our menstrual cycles with Kate Clancy, PhD, reproductive biology expert and period researcher whose life's work is advocating for menstrual health and wellbeing.
As we explore period myths, misconceptions and stigma, Kate sheds light on the latest research in menstrual biology, from the role of hormones to the microbiome of the uterus. We also discuss the cultural and historical factors that have shaped our attitudes towards menstruation and how these attitudes impact women's experiences today.
But we don't stop there. We also delve into the controversial topic of COVID-19 vaccines and how they may affect our menstrual cycles. Kate shares her insights based on the latest research, her own personal experience, and a survey she did which received 165,000 responses.
Kate and I discuss:
- Why she decided to study and dedicate her life’s work to menstruation
- Iron deficiency and periods: is there a correlation?
- The nuanced topic of period suppression and the implications of birth control Her infamous tweet about the COVID-19 vaccine, her findings, and her own personal experience
- Vaccine trials, research, and the dangerous lack of menstrual inclusion and acknowledgement
- Dispelling some of the myths surrounding what is considered a “normal period” and “abnormal” as it pertains to menstrual cycles
- The importance of paying attention to our bodies while also understanding that levels of variation in our cycles are to be expected
Dr. Clancy's work is a reminder that menstrual health is an important and often overlooked aspect of overall health and well-being. By increasing awareness and education surrounding this topic, we can break down the societal stigma and empower individuals to better understand and care for their bodies.
Thank you so much for taking the time to tune in to your body, yourself, and this podcast! Please share the love by sending this to someone in your life who could benefit from the kinds of things we talk about in this space. Make sure to follow your host on Instagram @dr.avivaromm to join the conversation. Follow Kate at @clancy_kate and check out her book at www.kateclancy.com
This conversation has been edited for clarity and length.
Aviva: I got my first period when I was 12. I was at my grandparents' house. It was a hot summer Saturday morning, and I was sitting cross-legged in a pair of undies and a t-shirt, and my brother four years younger than me, looked at me, started pointing at my panties and said, you pooped your pants. I looked down to see the brown stain, called him an idiot and ran mortified to the bathroom, thinking I actually had pooped my pants because no one told me normal period blood could be brown. From there, it sort of went downhill with my grandmother who could not say the word period. She could only call it a ‘hoozits’ or a ‘whatzits,’ kind of clueing me in on what happened. She went across the street and got to the supermarket there, got me some giant maxi pads, which at the time still required a belt, and she kind of bumbled her way through telling me about that. Then my mom came out and heard, I got my first period and true to Jewish traditions smacked me across the face. Fast forward a few years and I started to learn everything I could about my cycle being the hippie teenager I was, and I even learned how to track. Fast forward another 40 years to now, and my life's work revolves around helping women understand their cycles at all ages and phases in their lives.
My guest today also loves thinking, researching, and talking about periods and period myths. She even wrote a book on the topic called Period: The Real Story of Menstruation. Kate Clancy dives into the topic of periods with the lens of the anthropology professor she is, holding appointments in the Department of Gender and Women's Studies and the Program in Ecology, Evolution and Conservation Biology at the University of Illinois-Urbana Champaign, and at the Beckman Institute for Advanced Science and Technology. She's written for National Geographic, Scientific American, and American Scientist, and her book is a must read for anyone listening who's as geeky about menstrual health as Kate and I are, and who wants to more deeply understand the physiology, history and evolution of menstruation, and who wants to understand their own experiences of menstruation in the broader context of our cultural understandings, perceptions, and misperceptions. Kate, thank you for joining me.
Kate: Thanks for having me. Menstrual geeks unite.
Aviva: All right. I am hoping that you're willing to start out with really the first page of your book, which hooked me. I think it's the first page – taking the mystery out of menstruation. The tampon and lip balm study you open the book with and tell in the context of the responses you got is so telling about the stigma we've been steeped in about having periods. I feel like it reveals so much about why so many women still stuff that tampon up their sleeve on the way to the bathroom in public places. So can you just start with that study and what it says to you?
Kate: Sure. So Tomi-Ann Roberts is a researcher who I admire deeply and this study is such a classic to me in so many ways. Basically what happens is she recruited people, she and her colleagues, to do a study on what they thought was going to be group productivity. So people show up and they're going to be filling out a whole bunch of surveys and things like that. What they don't realize is that there is somebody that they think is going to be a partner for them in the study who's actually an actor, a woman who comes in with a handbag, and she comes into the room and she fumbles around in her bag and either drops one of two things, a tampon or a hair clip.
We've all been there where we're fumbling around in our bag for something and it's like it's just a mess. So she either drops a tampon or a hair clip and then just picks it up, returns it, gets out some lip balm, applies it and puts it back. The person who's sitting there, the way they're receiving this information is this person's fumbling around and just intended to get lip balm, but they were exposed first to a condition of either a hair clip or a tampon. Then they have them fill out all of these surveys again with the goals supposedly of group productivity, which is why they were being asked questions about their partner in the study, and they're asked questions around likability and other things like that.
Then at the end of the study, the actor sits down in a row of chairs. The idea is they're going into a waiting room, but there are just, if I remember correctly, five chairs along the wall. So she sits down in one chair, and then they paid attention to wherever that other person sat – how close they sat to the other person. What they noticed is two main things: the tampon dropping condition, the people who observed that were more likely to have negative perceptions of the person that they were working with, and the other is that they were more likely, this was not statistically significant, but it was a pretty notable finding that they were more likely to sit further away from that person.
We spend so much time hiding these experiences because of the ways that men have narrated to us, and other people who are in control of our cultural context or dictate to us what's considered appropriate ,have taught us over the years that these things are gross, disgusting and should be made as invisible as possible.
Aviva: So I've got to know, what got you geeked out about periods in the first place? Why periods of all things that you could have studied in anthropology and with that, what are some of the biggest questions you personally are trying to understand in studying periods?
Kate: I think there were two personal moments that were really notable. One that I talk about a little in the book, but I cut most of – there's there's only the smallest mention of it, which was when I got my period at age 13, age 13 in two months, I remember because it was the first month of eighth grade and my birthday is in July, so it's easy for me to remember even many years later. My mom proudly takes me to the nurse practitioner soon after getting my period for a checkup and says, “Oh, you know, Katie is menstruating now.” And Dr. Debbie says to me, “Oh, well now you need to start taking iron supplements because you're going to be low on iron now for the rest of your life.” And I was so struck by that. I was really upset actually in the moment, and I was like, why do you automatically think there's something wrong with me because of this thing I'm doing that half the people of the world are doing?
Something about it felt wrong. And yet for, I don't know, a decade or so or more, whenever I felt a little fatigued, I would say, I bet I'm iron deficient. And then I would go buy myself some iron pills and remember to take them for a week or two. So I had this narrative in my head that periods cause iron deficiency and any fatigue I'm experiencing is probably from that, not paying attention to the fact that I was probably only getting four or five hours of sleep a night and was not taking care of myself and other things. But also it meant that if I had had some other medical problem, I was not taking care of it in any way because I was just assuming that taking iron was would solve the problem.
Fast forward to when I was a graduate student and we just happened to be taking blood samples from these rural Polish participants that we were working with as part of a project on endometrial function that was the subject of my dissertation. I realized we had a chance to actually look at this in a real way. It had bothered me for so long and I thought, well, let's look to see if a person's iron status corresponds at all with how thick their endometria are, because I had these ultrasound measurements of endometrial thickness. My expected finding was that there would be no relationship. That was my hypothesis going into it. Instead, what I found was the actual opposite of what we've been taught is the case. So I found a statistically significant positive relationship that the thicker person's endometrium was then the more iron they actually had. So completely going into the opposite finding of what you'd expect if periods cause iron deficiency.
Aviva: Question about that. So the thickness of the endometrium would suggest that that person would then have a heavier period, and so that's where the anticipated iron loss is. So you did not find any correlation between – did you look at actually heaviness of periods, length of periods, and iron deficiency at all?
Kate: We didn't really have that data. So all we could really look at was this. And of course these are indirect measures. The other thing that's important about this study is there were only, I think 23, 25 participants in it. So even though it was robust within the context of what I had, it was certainly not adequate to telling the story.
But I then went to the literature and I was like, well, let's actually see what's going on. And within the realm of what's considered normal period blood loss, the literature does not actually show a relationship between a change in iron status and menstruation. It's only once you get into heavy menstrual bleeding, abnormal menstrual bleeding, menorrhagia, those types of labels – that you do start to see that. Absolutely, if we’re talking about pathological levels, you are going to see some iron loss. How could you not because there's tons of blood being lost.
Aviva: Right, and that's important because a lot of middle school and high school age girls, when they start menstruating, if they have heavy periods, that can affect their cognition, their academic function. So it is something important to be able to differentiate.
Kate: And the other thing that's important about adolescent periods is this is also a period of growth. This is again different from an adult-fused growth plates, no more maturation happening person and an adolescent who, because they are growing, their energy needs and their vitamin and mineral needs are probably greater in certain ways. I think you're really right to point that out that like a growing person, especially for instance, there's research that adolescent athletes in particular have greater iron needs than those who are not athletic. And that iron supplementation can be very useful for them. And that's because of the fact that they are exercising and menstruating and growing.
Aviva: And have more muscle too, which has more oxygen demands from the exercising itself.
Kate: What that tells us though is that it's not menstruation that is the demon that is taking away our iron. What we're seeing is that if you combine 3, 4, 5 variables, then yes, menstruation is one of them, under certain conditions, that might be worsening iron.
But there's one other piece of evidence that I think is really important, and I think we didn't get to keep this in the book for space, is that one of the other things that's important to understand is that one of the reasons we see a big sex difference in iron stores and iron deficiency is not because people who menstruate their iron necessarily dips precipitously when they start menstruating. It's that those who hit puberty and have testes and have an increase in testosterone actually see a rise in iron status because of the ways the testosterone promotes oxygen transport.
And so the sex difference is not menstruating people are experiencing a drop. It's that non-menstruating people, especially those with testes, are experiencing a rise. So again, we're pathologizing what's kind of a norm instead of acknowledging that actually this difference just has to do with the fact that these folks have testosterone.
Aviva: So what was the moment where you were like, okay, I'm going to dedicate my life to studying menstruation?
Kate: I would say my sophomore year was a really formative time. I had just declared for a joint major in biological anthropology and gender and women's studies. And one of the required things you'd had to do as part of the Bio Anth major was take some type of upper level seminar. I wanted to take this reproductive ecology seminar. I didn't know what it was, but that sounds cool because I think reproduction is cool. I want to study this. And it ended up being one of the best academic experiences I had in all of college. It was taught by Dr. Susan Lipson and we got to do lab work – it was the first time that I got to conduct my own research and run assays – and there was something about that process of achieving some independence, getting to ask a research question, design a project and implement it that was hugely useful and confidence building. It's one of those things that I feel so passionately about as a professor is that I know that that path to independence is exactly what makes people realize that science is for them.
It was a really big moment for me is getting to see, “Wait, people study this for a living? They study menstrual cycles and hormones and I could just learn about this for my life? This could be what I do?“ And that's kind of what hooked me in a lot of ways is this idea that I had these people I could learn from for the rest of my time in college, that I could actually keep studying it in grad school. I had no idea a path that was available to me until I took that class.
Aviva: I wasn't even aware until some years ago that reproductive ecology was actually an entire field and it's super fascinating. What are some of the biggest questions that you find yourself asking?
Kate: One of the big questions for me, and it's one of the things that I talk about in the book is thinking about the kind of the purpose, the physiological purpose of menstruation. I've been perplexed/angry around the narrative of the evolution of menstruation, why it evolved, the physiology of menstruation, because we started from this historical viewpoint from multiple centuries that menses was about removing gross stuff from the body. It's like removing toxins or seeing people who menstruate as inherently toxic and you want to remove it. It varied and depending on the cultural and religious context and what century we're talking about, this removal of toxins was viewed more benignly versus more antagonistically, but it was still there. All through the 20th century this was considered a legitimate way to understand menstruation. There was this thing that people were convinced they could find if they could just isolate it called the menotoxin, and if they could isolate the menotoxin, they could figure out what it is that's so toxic in the bodies of people who menstruate.
But from there into the late 20th century into the nineties when I was actually finishing up high school and heading off to college, there entered this new way of thinking about it and I'll just telling the short version. What ended up happening is we started imagining different ways of telling this story. We started, instead of seeing women as inherently dirty, we started saying, “Well, what if the pathogens and the dirtiness is coming from sperm?” Another argument that came about was what if this is an energetic argument, so it is more energetically costly to maintain the endometrium than remove it every cycle. There was a hypothesis around, well, maybe this is actually a form of… this is another reproductive bottleneck where this is a chance to remove chromosomally abnormal embryos.
But where it seemed a lot of people settled in the late nineties into the early two thousands was that periods are in fact useless. Endometrial cycles did evolve; they are a necessary component of menstrual cycles. We need that growth and differentiation to have somewhere for a trophoblast to land, but periods itself, that's just like excess, that's just excess fluid. There's nothing actually meaningful going on there. And so this useless narrative was persistent throughout my entire training, and it wasn't until, I think the first paper I saw on this came out in 2012 where people started to say, “Well, what if actually menses itself has some purpose within endometrial cycling?”
That was huge for me because it was like, well wait, maybe periods actually have some kind of purpose. And it turns out that a lot of the cytokines and other inflammatory biomarkers that are present within menstrual blood are themselves important parts of the healing process that happen during menstruation. I love that narrative because it shows that the fluid isn't just like excrement or effluent, it's not just stuff that you remove. It is actually necessary to the process of growth and regeneration that powers the next cycle. So to me, it's actually a really cool narrative. It recenters periods as being really important and it shows that endometrial cycling and menstruation itself is potentially a very important component of fecundity and infertility.
Aviva: Presumably that endometrial lining based on what you're saying is healing and regenerating so that should a person become pregnant in the next cycle, they have an optimally healthy endometrial lining. If someone is on a continuous contraceptive hormone for full suppression, quarterly or a year long, clearly they're not trying to become pregnant or they're avoiding it intentionally. Do you think that there are any long-term concerns or repercussions of either just a monthly pill or on the longer-term suppression at this point from your research?
Kate: I think this is to me a really important open question. I would hesitate to vilify a treatment that is so important to so many people and is crucial to reproductive autonomy, and helps resolve symptoms for people who really need menstrual cessation. And so I think it's possible for us to have nuance here.
We can hold that in our head while also saying, if fertility is a future goal for you, we need to actually start testing some more rigorous hypotheses around this because there is indirect evidence, so not direct evidence, but there is indirect evidence that fewer menstrual cycles, fewer periods might potentially correspond to pre-eclampsia and certain other issues down the line. And that's because if you aren't giving your endometrium lots and lots of times to practice creating all of that cool tissue infrastructure, then they won't be super developed at doing it by the time a little trophoblast comes along and wants to implant. So we have to consider that periods are an actual form of practice that is necessary to and very helpful to the trophoblast invasion and implantation that happens in pregnancy itself.
But I want to be clear, and I try to be clear about this in the book, I see this as a working hypothesis, not as me trying to make some kind of ultimate statement that this is absolutely the answer, but that we aren't paying any attention to this. We are not putting sustained attention on this and think that's a problem.
Aviva: I agree. I totally agree with what you're saying about the importance of access to and for many people use of the Pill for symptoms and for contraceptive control. And I also frequently use that statement, we can hold two different things at the same time.
From my end of it, I see so many women who come to me in their mid-thirties or early-to-mid-thirties, who were put on the pill at 13, 14, 15 and just left on it. Most of them come off the Pill, their fertility returns. It's no problem. There is a subset, though, that I definitely see that does struggle. Perhaps it is that those people were already having symptoms of something like PCOS that were showing up, which is why they were put on the Pill in the first place, and that was suppressed and now they're off it and it's resurfacing. But I would love to see more research on just this sort of longitudinal, almost seemingly ad infinitum use of the Pill.
I'm assuming that, but please clarify this. When we become pregnant, we also are having suppressed menstruation for 10 months or however long that pregnancy lasts – could be shorter, someone has premature birth, etc., miscarriages – but some people have 6, 7, 8 babies, so their cycles are being suppressed as well. But something different I'm assuming is happening in the endometrium that may be different than these practice cycles that are missed. Is that correct?
Kate: Well, because the pregnancy is sustained practice for any future pregnancy. If you're having nine months of, I mean those first three months are all working on endometrial architecture, making the placenta, there's so much that's happening just in that first trimester, but even up through the third trimester, there is continued endometrial remodeling happening throughout the entire pregnancy. That means that it is doing that work, right? It's getting nine straight months of that architecture instead of say just a couple of weeks per cycle where it's potentially doing all that differentiating and remodeling work.
And so to my mind, that’s the difference is that if you have eight pregnancies and only a handful of cycles in between, each of those pregnancies is still representing a massive remodeling of the uterus. So in some ways perhaps comparable to having 8, 10, 12 cycles for each of those pregnancies. Maybe just in terms of thinking about, I have no idea what the actual one-to-one, this is where I would love to see more research done on this to better understand tissue remodeling. It's why I have a whole other collaboration actually with tissue engineers. We're trying to produce endometrial scaffolds to mimic the endometrium in sort of 3D scaffolds outside of the body so we can try to study it and understand it better, so that some of these questions can be better resolved in the future.
Aviva: Very cool stuff. It sounds really fun, and especially for people who love to be in the lab, anyone who's listening and hearing about assays, I mean, the first time I did a gas chromatographic study, I was like, wow, this is so cool. It takes a certain love of science to be at that level of granularity, but it's really fun if you like puzzles and Tetris and all the things.
All right, the first time I think I heard your name was in February of 2021 when you tweeted out a question: Has anyone else had changes in their periods since receiving the Covid-19 vaccine? And I was so glad you did because as a physician, I was feeling like I was straddling the line between vaccine advocacy and support for people who were struggling with the decision and also being really honest and clear about what I was also hearing, which were women writing to me saying, I've gotten the vaccine and now I've had two periods in a month. I haven't had a period in two months. I'm having a much heavier period, all the things. So you got an avalanche of replies and you and a colleague put together a survey – you got 165,000 responses on people's post-vaccine menstrual experiences. First, what prompted your Twitter post and then what were the key findings from the survey?
Kate: Sure. So there are two things that prompted the Twitter post. First is that my colleague and a former student of mine, Katie Lee, who's a professor now at Tulane, she messaged me first about it. She had had the vaccine several weeks before me, and she and her friends had a little group chat going where they were discussing symptoms and she noticed that several of them were saying, “I have an IUD, but I had breakthrough bleeding” or “I'm having the worst period of my life right now.”
So she messaged me about it and I was interested, but I was also like, I'm living my life and I just want the vaccine. I'm still waiting for it to be open to me and available to me, so I'm not even ready yet. But then sure enough, just a few weeks later I got the vaccine, and a week and a half after that got my period and had the worst period I've had in so long. I mean, I still remember the sensation of just sitting in my chair and that exhaustion, just that wave of exhaustion…
Aviva: Bone weary. That's what I call it, yeah.
Kate: You can just feel your period just flowing and flowing out of you where you're like, how am I producing this much volume right now? It was just so much blood and I was swapping out overnight pads. I would run between Zoom meetings to the bathroom and I could not get over how heavy my period was. And so I was just, so between Katie's comment and then my experience, I was just like, I got to Tweet about this because I'm an extremely online person.
It was a huge response. And the thing is that, as someone who studies the uterus and studies periods, I was initially trying to think through what would the mechanism be here? And I had some great conversations online with other colleagues about this. And really where we arrived is that it is actually a completely rational assumption that an extremely immunogenic vaccine like these mRNA vaccines that invoke – which we want them to do – invoke a very strong response, are going to have all sorts of potentially unexpected downstream temporary side effects.
Now think about the uterus, which is an immune organ and it's a hemostatic organ. Like bleeding and clotting, it's what that thing does. And what is one of the things that invoking the immune response does? It changes bleeding and clotting. So how is it not one of the first things that we look at when we do any type of vaccine trial, that we look at the effects on the uterus and we see if side effects are there. And yet the way vaccine trials are designed, I very quickly learned by talking to science writers who are friends of mine who cover the vaccine beat, and talking to people I know who do vaccine trial research, it very quickly, quickly became apparent that it is almost impossible with current methods to actually study the menstrual cycle during vaccine trials – one, because they often suppress the menstrual period or suppress menstrual cycles through hormonal contraception, and two, because they ask zero questions about it. There's very few open response opportunities to volunteer this information if you experience it yourself.
The more I thought about it, the more my colleagues and I talked about it, the more flabbergasted I was that this is not an incredibly common thing that we look at alongside sore arm, fever, fatigue, other types of short-term temporary changes that have to do with elevating your immune response so that we can, in terms from a public health perspective, so that we can inform people what to expect so that we can just be more deserving of their trust and be more likely for them to actually take the vaccine and help us with this giant public health concern.
Aviva: It's just sort of one more story in a long line of failure to include women in research trials, to acknowledge menstruation as an important factor in our health, but also one of the reasons that women historically were excluded from research trials was at least blamed on the fact that our menstrual cycles make us unpredictable and irregular. So it's sort of like this tautology in a way of explaining why we're still not included, even though it's really important. And I think the menstrual changes ultimately being discounted further added to mistrust of the medical system and the vaccine. The survey got a lot of media attention, but it seems like you might have gotten a significant amount of pushback and dismissal about the possibility that there could even be a link between the vaccine and menstrual changes.
Kate: What was interesting about this is I have a PhD from a fancy institution. I have a huge list of publications to my name suggesting I've got significant expertise here, but I'm not an MD.
I was seen as a non-expert or a silly lady with my silly lady feelings. And MDs were constantly positioned as experts and I mean, I don't know almost every single story that talked about this. We had national and international media attention. They would interview an MD and they would interview us. And every single time the MD had one of two responses, and I create a PowerPoint slide when I talk about this, they either said there was no biological mechanism, in those exact terms, or they would say it's just that the pandemic is stressful and that stress is what is making people think it's the vaccine that is affecting their cycles, but it's pandemic stress. So it was either there's no mechanism or these silly ladies with their silly lady feelings. And those were the only two responses.
Aviva: The mechanisms seems so obvious to me. And the other is just dismissal, dismissal, dismissal, dismissal.
So one of the things that we saw with the vaccine during Covid that came out in people's reports was heavy bleeding. Some people just reported that they had irregular menstrual cycles. And I'd love to switch gears and just talk about irregular menstrual cycles and what that really means because there's so much misinformation that leads women to not feel normal when in fact they may very well be.
There's a huge variability in the menstrual cycle. The wellness world has also gone to town telling women that there's basically a perfect period – our periods should be a certain color, never a clot, some people even say it should occur at the phases of certain phases of the moon. And there's a lot of biological reductionism. I talk about, in my book ,Hormone Intelligence, that there's no such thing as one normal menstrual cycle or a normal period – that variation is huge across individuals.
And there's one interesting study that you mentioned in which women were interviewed about when they got their first periods, and hardly any of them said they'd gotten it “on time”. I'm doing air quotes here.
Nearly everyone ends up feeling abnormal about when they start their period. I have patients who come to me and they say, well, my period is every 25 days, so it's abnormal and irregular. I'm like, if it's every 25 days, that's actually within the range of normal. It may feel a little frequent to you and we can talk about that, but it's not abnormal. So what has your research shown about the natural variations that happen and how does the myth of the normal menstrual cycle or perfect cycle actually hurt us?
Kate: I actually think that there is an important intervention to be made to contest some medical views of the body because people who menstruate are so much more likely to experience medical betrayal and medical gaslighting. What that does is creates an opening for plenty of legitimate and important ways of thinking about variation, indifference, but also it actually creates room for charlatans and people who just make stuff up for funsies and try to make money on Instagram off of it, like “follow my hormone program and you'll have a period with no pain and periods.” I've seen some of these ads where they're like, periods should not be painful, and if you take my herbal supplement, you will end up with the perfect normal period or whatever.
Aviva: Well, I would argue that I don't think that it's normal to have horrible period pain. I separate normal and common. I want to circle back around to this concept of the Sixth Vital Sign that we accept a level of pain around periods in our teens and in our adult lives that can be so significant that we still are telling ourselves or our doctors tell us it's normal when actually we are missing endometriosis or adenomyosis. The way I differentiate it is that periods may be crampy, uncomfortable, you may have a heavy dragging sensation, there may be occasional sharp cramps, but overall, I wouldn't say it's a horribly painful period is a normal period – especially if you're having to take medication every month or miss school or miss work or… so I'd love to hear what your thoughts are on that and then maybe we circle back around to this variation.
Kate: Yes. No, I think you did a great… thank you for saying that you did a great job differentiating between is this normal versus common and does it interfere with your quality of life? And most people who do research on endometriosis and other things like that, and menorrhagia – that's the question more so than trying to quantify how many lesions do you have or how many milliliters of menstrual blood do you excrete – or something like that, which used to be a really big part of the metric for determining how pathological you were. Now they're really asking lifestyle questions. How many days of work are you missing? How many days of school are you missing? How much ibuprofen are you taking? How much is this interfering with your quality of life? And I think it is important for us to acknowledge that we shouldn't have to experience a massive shift in our quality of life and that we should be able to expect that there are ways that the world can better accommodate us and that we can get better support for these symptoms.
Aviva: I wish we could have a culture and a world in which people who menstruate could just know that if they needed a flex couple of days off, no explanation needed for those days, without it then becoming this sort of reinforcing negative belief system around people who menstruate needing special compensation and special dispensation. And see, it is the weaker sex. It is all the things that are the historical misconceptions.
When it comes to some of the myths that you've seen perpetuated around this sort of normal period or perfect cycle, what are some of the ones that concern you and some of the big menstrual myths in general and misinformation that you'd love to dispel through your work?
Kate: I do think one of them is definitely this idea that there is only one way to have a menstrual cycle and that it's a 28-day cycle with a 14-day follicular phase and a 14-day luteal phase, and that that's the only way to achieve normality or fecundity. We study menstrual cycles in our lab all the time. We have literal freezers downstairs from where I am right now full of pee. And the hormone analyses we've done have shown that there are plenty of people who have had children, so proven fertility, who have hormones that look completely different than what we've seen in textbooks. We've been conducting some really cool analyses in our lab over the last couple of years. We have a couple of posters out, but we have several papers that we're about to submit in the next month on this. We've been doing something called geometric morphometrics, which is a particular approach to understand shape.
And I talk a little bit about this in the book, but basically what we're trying to understand is when you average a whole bunch of people together, those hormones through the menstrual cycle look like what you see in a textbook. But then when you look at any one individual, it doesn't look like that. So our question was, is there just lots of variation and everybody's different, or is it that actually you can sort people a little bit statistically into real pheno groups where there are some slight differences in shape that might tell us a little bit something biologically about some of these different types of bodies? And what we found was the latter. We had a sample of Polish and Polish American folks, just because that's where I've done a lot of my work and where my students have done a lot of their work, and we found that within that sample we could sort people into about three groups based off of their estrogen and progesterone metabolites that we were measuring in urine.
Aviva: Okay, so what have you found in terms of these hormone shapes? And to clarify for listeners, because we may do some editing to clarify for listeners, these aren't body shapes. These are the shapes of the hormones as they're mapped on these graphs or images.
Kate: So if you've ever seen one of those graphs that shows here's what estrogen is doing, here's what progesterone is doing. In a lot of medical textbooks, a lot of health and sex ed materials that children receive, we see estrogen do this big peak at mid-cycle and then a little bit of a luteal phase bump. And then progesterone just has this one big luteal phase bump. We've seen some big differences in the width of the peak of the estrogen peak. We've seen some big differences in luteal estradiol, and we've seen some big differences in the shape of that big progesterone curve that's happening in the second half of the cycle. It’s not there are only three types out there, it's that depending on the sample that you're working on, the stats are going to show slightly different sorting. But those are basically the variables that we're noticing are ones that seem to change among these different groups.
The other related thing is we've started to do similar research looking at c-reactive protein through the menstrual cycle. So this is an acute phase protein that is often used as a biomarker for systemic inflammation. And then we also have some data on cortisol and cortisol variation through the menstrual cycle. A couple of big findings here. One is that some of our prior work has shown that CRP is elevated at menses, and we've now done some work replicating that in the second population is that among certain populations, because of all the tissue remodeling that's happening at menses, that's a time you're going to see a spike in CRP. But then the other thing we're finding with cortisol through the menstrual cycle is that we can sort people into different groups where you can see that the cortisol variation is clearly mapping onto ovarian hormones for some individuals and for other individuals, nothing – completely unrelated to ovarian hormones.
And so a couple of the things that we're thinking about are the ways in which we want this tidy narrative of a normal menstrual cycle that is this many days long and our hormones are doing this, and the menses is doing this, and that's normal. And we want these narratives that show this is what the systems in your body – everyone reacts the same way. An appropriate body is one that reacts to hormones, or maybe an appropriate body is one that is non-reactive to ovarian hormones. That's probably more the norm, culturally. We don't want a body that reacts to our cycle in any way.
Instead what we're seeing is a huge amount of variation in the extent to which people's hormones, people's downstream stress hormones, and inflammation are responsive to cycle variables.
Aviva: What do you think are some of the clinical correlations or clinical relevance of all of this?
Kate: So two things. When it comes to the CRP information, if CRP spikes at menses for some people, and you're doing blood work where you're trying to see whether or not somebody has cardiovascular disease and you decide to measure them at menses, you might end up with an elevated CRP reading compared to the rest of their cycle. So to me, the clinical significance there is we need to be understanding a person's last menstrual period or whether they're currently menstruating when doing those kinds of blood work panel assessments.
With the cortisol finding, what that's really pointing us to is to us, we see a lot of this work as really commensurate with some of the work that people are doing on PMDD, which is showing that a percentage of people happen to be very responsive to ovarian hormones and fluctuations in ovarian hormones. But not everyone.
I'm sure you're familiar with the fact that for both premenstrual dysphoric disorder and postpartum depression, initially people thought, oh, what's going on here is people are responding to that extreme drop in progesterone, except everyone's experiencing that extreme drop in progesterone, but only some people are having this effect. And what we're now starting to notice is that what might be happening is some people are very responsive to ovarian fluctuations and some people are not. What we need to start to understand is why are some people super responsive and some not, because that might help us predict and then help people who are going to have these kinds of issues downstream.
Aviva: And you haven't found any correlation yet suggesting that the people who have the higher cortisol response are either more protective or they're having more of a stress response?
Kate: No, not yet. No. This is still just establishing what is the range of variation in a given sample and how does that help us start to think about this kind of big debate that keeps appearing and reappearing over the last couple of decades, that you referred to earlier around, “Oh, well, we can't study women because they have menstrual cycles and that's so tricky to control for all that variation” or “Menstrual cycles actually don't produce a ton of variation.” There are two competing narratives out there in terms of rationales to include cycling people. One is we should understand that variation and it's profound. And then another camp that's still arguing for the same thing which is we should include them because we should be including everybody, but the cycle stuff is meaningless.
And what if the answer’s somewhere in the middle, which is that cycles are very meaningful for some people and not super meaningful for others, which then confounds any ability to come up with special cycle syncing suggestions and here's how, one of the other big fitness influencer things right now is cycle syncing your workouts. If you're a person who's not hormonally responsive, how is that a useful thing for you to pay that much attention to what's happening in your menstrual cycle when you're weight lifting versus doing Pilates or whatever?
Aviva: I think the biggest benefits of – and cycle syncing is, again, one of those things that somebody literally made up branded and sells products around – I think the advantage is that it's almost like the opposite of the decades or centuries of ignoring our menstrual cycles. It provides people with an opportunity to pay attention to them, think of them in a more lifestyle integrated way. And I think if that is helping people to be more mindful of just their lifestyle in general so that they do feel better and are more just in tune with their cycle if they want to be, I think that's the advantage.
But I do think that there's a lot of misinformation and hype that I spend a lot of time in my clinical practice addressing things like the DUTCH test, which is very reductionist, that you're going to check your cycle, your hormones at home with this tiny spot test and basically know everything you need to know about what supplements to take, how to eat, how to exercise, how to pick your life partner.
It's just not true.
So in my book Hormone Intelligence, I provide some evidence around the AAP and then ACOG making this important, what I felt was a very important statement, where our menstrual health is a vital sign, especially for teenagers. They were really focusing in on teenagers. And the concept is that if we see our menstrual cycles as a vital sign, then we're more apt to, as we talked about earlier, recognize things like endometriosis or polycystic ovary syndrome earlier and be able to be more preemptive.
I also take this vital sign concept to an even deeper level of saying, “Okay, what is the menstrual cycle reflecting about a young woman's or woman of any age’s total health ecosystem that can give clues to underlying health. And in your book, you do talk about many of the things I talk about in Hormone Intelligence – diet, nutrition, stress, environmental exposures, and you have lab studies that demonstrate that these various environmental stressors can impact the menstrual cycle. For me, in the book, I bring a lot of these back to factors that all kind of contribute to inflammation ultimately. Can you talk about your thoughts on this idea of the menstrual cycle as a sixth vital sign or a vital sign, and also the findings that you feel it's most important for women and teens to know about so that we can protect our menstrual health?
Kate: I think, again, kind of getting back to this idea that we can hold two ideas in our head at once. I think it's possible to understand these environmental factors that influence menstrual cycles and have that be informative to us becoming more in touch with our menstrual health. And I'll say the other way that I think it's important to think about these environmental factors and how they affect menstrual health is they should allow us to actually worry less about variability.
If the way menstrual cycles evolved was to be responsive and that flexible responsiveness is actually inherent in the adaptation, then variation is not bad. And on the one hand, yes, extreme amounts of variation like amenorrhea for multiple months is absolutely a sign of something going awry enough that we should be paying attention and saying, “What are the stressors or other things going on in our lives that we are experiencing such a large shift in our experience of our cycles?” But what it should say is that when we are experiencing variation, we don't have to feel so precious about it. In my opinion, I actually don't think we should be putting tons and tons of effort on figuring out how to resume some particular way of having a menstrual cycle. Because all that does is continue to pull us towards this idea that there is one correct way for the menstrual cycle to be, our body is supposed to respond to stressors. And so it's okay to vary.
Aviva: Yeah. So it sounds like the big takeaway is that we can relax a lot about the variations in our menstrual cycle as long as they sort of stay within a container of what is considered healthy and in the context of how we feel, how we're experiencing our menstrual cycle, whether it is actually interfering with our quality of life.
Kate: Right, and again, that quality of life is the marker to really be paying attention to as opposed to it's two days different, three days different than another time.
Aviva: Kate, thank you for a fascinating read. I'm really thrilled to have all this science at my fingertips and all this data and all this cultural and social and medical anthropology. I wish you the very best with this book, and I hope we can have you again, because I know your research is going to keep evolving. So it'd be interesting to see what you're talking about in a few years. And thank you for the important work you did helping women to feel validated around their experiences with Covid vaccination altering their menstrual cycles.
Kate: Absolutely. Thank you so much.
