The Vulvalution

The menstrual cycle: What you really need to know

• Season 1 • Episode 4

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What actually is the menstrual cycle—and why does it matter?

In this episode of The Vulvalution, we’re joined by endocrinologist Dr. Jerilynn Prior to break down hormones, ovulation, and the menstrual cycle from a whole-body health perspective. We bust common myths, explain why estrogen and progesterone work as a team, and walk through a full cycle—covering cramps, PMS, ovulation, and why your cycle is about much more than reproduction.

If you’ve ever been told “it’s just your hormones,” this episode is for you.

📚Episode Resources: 
Documenting Ovulation with Quantitative Basal Temperature: https://cemcor.ubc.ca/resources/documenting-ovulation-quantitative-basal-temperature-qbt/  
Interested in participating in research? https://www.reachbc.ca/ or https://whri.org/

Mathilde:

what is a menstrual cycle and why do we have one? Why is it so important to have a menstrual cycle? A cycle

Dr. Prior:

It's our way of getting the Sex hormones that our body needs for the functioning of every tissue. You know, hair, skin, brain, heart, Bones, everything

Mathilde:

what is normal bleeding and if the bleeding is more red or if it's more brown, what's considered normal?

Dr. Prior:

What are cramps and what's causing them? Cramps are the uterus contracting. In fact, the understanding in the general, specialist literature is that you only get cramps if you've made an egg, if you ovulate it in that cycle. But that doesn't make a lot of sense since cramps are worse in teenagers who don't always ovulate. Mm-hmm. If you could bust one myth about women's health forever, what would it be? That estrogen is the most important hormone.

Mathilde:

Hello, VIS squad. Today we're diving into one of the most fascinating and misunderstood aspect of women's health hormones and menstrual cycle. We are lucky enough to be joined today by Dr. Jerilynn Prior, an endocrinologist who studies menstrual health. An endocrinologist is a doctor who specializes in understanding how hormones work and how they interact with each other. And we're gonna talk about this today.

Sabrina:

Dr. Prior is a professor emerita of endocrinology metabolism at the University of. British Columbia is the scientific director the Center Menstrual Cycle and Research. She has special interest in the effects of on women's health and one of her areas of research is menstrual cycles. Dr. Prior is widely sought as a public speaker and has written several books on perimenopause, menopause, and women's health. So Dr. Prior, welcome to the Vulvalution. Thank you. I'm happy to be talking with you. Yeah, we're so glad you're taking time out of your day to speak with us, speak to our audience, up speed hormones, they are, what the menstrual cycle even is. So we are thinking, you start by us a bit about your background and what you to endocrinology? Specifically the women's health field.

Dr. Prior:

I came at medicine from a very strange place. I grew up in a small fishing village in Alaska where we had no healthcare at all. I think I came to endocrinology because it was complex and it integrated everything and I was, I wanted to understand it better. I came to women's reproductive endocrinology because I saw a huge gap, and maybe that began with one of, or maybe several things in my own history. One is that I got my first period on my 13th birthday, another is that I lost my period when I went away to go to university, and I had enough smarts to know that I was healthy and well and not pregnant, and therefore never told a soul And the third one was that I had a horrifying experience with the birth control pill of the day in 1967, and therefore understood because it was a very peculiar pill that was estrogen only. And then they added the progestin later. So from that experience, anytime anyone told me some glorious thing that estrogen did, I said. Show me, prove it. Because I knew it could be extremely negative.

Mathilde:

First let's talk about hormones and sexual hormones. 'cause I think a lot of our audience don't really know the difference between, what is a hormone and then what are the different hormones?

Dr. Prior:

So hormones are. Chemicals of some sort. They can be different, chemistry, proteins, fatty hormones, et cetera. Steroid hormones are very complicated and complex, but important. And they are created in one tissue. They're spread usually through the blood system and have effects in other tissues. That's what hormone means, right. People sometimes say

Sabrina:

they're like messengers. Do you that that's a good analogy. Yeah, that's fair. they're almost like the messengers of the text messages that go between different parts of the body. Yeah. They're, they're taking the instruction from one tissue to another. Can you give us example what kinds of effects hormones can have on the body? The examples are as many as the sea is big because they affect things that are rather subjective, like mood, attention. Also things like, making another enzyme or making insulin,

Dr. Prior:

They affect change in almost every tissue. You can't live without

Mathilde:

'em. Mm-hmm. And then some people often talk about hormonal imbalances. Do you know a little bit what that could be? Or if it's actually a thing or not?

Dr. Prior:

Oh, of course it is. Because there's no black and whites in physiology or biology. It's always a balance, which is, one of the unique things, about the menstrual cycle. You call them sexual hormones and we think of them as having to do with reproduction, making babies, and I guess as part of the sex response, which is also true, but if you actually get to thinking about it, the hormones made by the ovary are there to provide us with the estrogen and progesterone that every part of our body needs.,

Mathilde:

Oh, so not just a reproductive system.

Dr. Prior:

Yeah, we need it from. Our first period starts before that, but that's the sort of milepost through to menopause and it's a huge chunk of our lives. the longer the reproductive span of a person is the healthier in general they are.

Sabrina:

in women, each cycle is made by a different set of cells surrounding an egg. So each cycle is unique, that they're reproducible, predictable at all is absolutely amazing. And it shows the careful feedback between the hypothalamus in the brain, the pituitary and the ovary, that there is any reproducible predictability about a menstrual cycle. Huh

Dr. Prior:

I was thinking we could play a little game to get people familiar with hormones in general, because I think people hear about lots of different hormones, whether it's an insulin, but they don't

Sabrina:

understand what they are. I'm gonna do is say of a hormone then I you to use one word to kind of give the vibe that Okay? Okay. Um, the first one is adrenaline or epinephrine speed. Okay.

Mathilde:

Okay Yeah. Cortisol

Dr. Prior:

stress, Insulin sugar.

Mathilde:

Oxytocin,

Dr. Prior:

Oxytocin. Bonding.

Sabrina:

Mm,

Mathilde:

ghrelin

Dr. Prior:

appetite.

Mathilde:

Estrogen

Dr. Prior:

Cell growth. Okay. That was

Mathilde:

great. Let's add progesterone.

Dr. Prior:

What do you think of I think overlooked. That's true.

Mathilde:

Maybe like the stopper. 'cause you mentioned that estrogen is very much building. I

Dr. Prior:

the general assumption is it's progest just promoting gestation, which means pregnancy. Mm-hmm. And the general assumption is progesterone only works in the uterus. It changes the lining of the uterus so that an egg could implant and it preserves a pregnancy once, a fertilized egg is implanted. And. Uh, you'll even find contemporary scientific research that refers to it that way. My understanding, and it's taken 47 years probably to get there, is that it works everywhere in the body that estrogen does, and estrogen receptors are everywhere from the brain to the eyeball, to the, you know, you name it. They're estrogen receptors and wherever their estrogen is acting, progesterone is also acting. So maybe the word is widespread effects. Absolutely. Absolutely. Okay. And, and what you referred to is that these two hormones are part of a system. They either counterbalance or compliment each other's actions. Let me give

Mathilde:

Let me give a

Dr. Prior:

a simple example. Estrogen decreases bone resorption or bone loss. Progesterone promotes bone formation. So there's an instant where they do different things in the same process. Right, right. Both of them actually improve endothelial function, which is a control of blood vessels and blood flow, which is crucial for heart health. Um, that's another one. But in certain things like breast cancer and probably breast cancer and endometrial or lining of the uterus, cancer, progesterone prevents the cancer that estrogen could form. Right. Interesting. So

Mathilde:

sometimes when things

Dr. Prior:

get out of balances, that progesterone might be the safety or the mm-hmm. Mm-hmm.

Mathilde:

that brings it back. Mm-hmm. So in other word could be protector,

Dr. Prior:

Protector is right. If someone was to come into your office as an endocrinologist

Sabrina:

and wanna learn about sex hormones, the menstrual cycle, are the basic hormones they would have to know about in order to understand menstrual cycle? Okay. The basic ovarian hormones or estradiol, which is the premenopausal form of estrogen. Estrogen actually has three forms. Estradiol, which is during the menstrual cycle, estriol, which is a pregnancy type hormone, and estro, which is the menopause one. Okay. That's good. Differentiation Mm-hmm. Mm-hmm. And then progesterone and progesterone. So 17 beta estradiol and progesterone are the main ovarian hormones. The pituitary ones that. Sort of do the, the direct, management system, if you will. Or luteinizing hormone and follicle stimulating hormone. And they are directed by a single hormone in the hypothalamus called gonadotropin releasing hormone. So if

Dr. Prior:

I understand correctly, gonadotropic releasing hormone stimulates the two other ones. Mm-hmm. Or controls them. Or controls them. Mm-hmm. And that controls the arian. And what's another interesting thing is we change from pulsation, which is the way the nervous system communicates to typical hormones going through the blood system. By going from the hypothalamus, it signals to LH and FSHR pulse related. Okay. Okay.

Mathilde:

Super interest. And can we make a quick note on hypothalamus? Where is it? What is it? Just so that

Dr. Prior:

it's in the base of the brain. Mm-hmm. Close to the pituitary, which is right behind the bridge of your nose. Oh. Between your eyes. I think that shows how, how far and

Mathilde:

how diverse hormones communicated. It's not just in your reproductive system, right. It's across your whole body. Yeah. Okay. So now we're gonna move on and talk about the menstrual cycle. So let's start with, just when we go back in history, the menstrual cycle was often seen as dirty or, people weren't talking about it, or it was seen as even dangerous

Dr. Prior:

And there are still some cultures in the world today that view women who are menstruating as toxic unclean or unclean. Mm-hmm. I mean, just an example, I worked in Barrow Alaska and they did not allow menstruating women out in the whale boats.

Sabrina:

They think

Dr. Prior:

it was like cursed or, or, yeah. Bad luck or something Interesting.

Mathilde:

And I read somewhere that sometimes they, some people call them menstruate. So instead of just being your name and your person, you're just a menstruate,

Dr. Prior:

Yeah. I hate that when you identify a person by a

Mathilde:

Mm-hmm. Condition

Dr. Prior:

that is not okay.

Mathilde:

No. Okay. Firstly we wanna ask you, what is a menstrual cycle and why do we have one? Why is it so important to have a menstrual cycle? A cycle

Dr. Prior:

is the process starting from the maturation of an egg. It gets bigger and bigger. It gets about an inch across with mostly fluid in that two layered follicle. It's migrates to the outside of the ovary is released. So following that is the beginning of making progesterone and the luteal phase. So the whole process is between three and five weeks long, or 21 and 35 days with truly an average of 28 days for once. There's a myth. That's true. And why is it important that we have a menstrual cycle? It's our way of getting the, hormones, the, the gonadal steroid, I don't call 'em sex hormones, but sex hormones that our body needs for the functioning of every tissue. You know, hair, skin, brain, heart, Bones, everything requires needs. Those two hormones. Right. Okay. We were thinking to give our listeners an idea of how the menstrual cycle works and what different things might happen throughout it, that we could go through a hypothetical menstrual cycle, and we invented a friend named Belinda who has maybe a typical 28 day or average 28 day cycle, and we were thinking we could go through, maybe ask you some questions about what's, happening hormonally, what's something you'd be experiencing during that time of the menstrual cycle? Mm-hmm. How does that sound? That sounds great. Perfect. Okay. So starting at the very beginning of the Linda's cycle, and I don't know if you say this is the beginning versus the end, but we're starting right at the beginning. The beginning is the start of flow. Yes. Okay. So that would be the beginning of your menstrual cycle. Cycle day one. Cycle day one. Perfect. Okay, so she starts bleeding. First of all, why is bleeding?

Sabrina:

bleeding?

Dr. Prior:

The physical thing that's happening is that the lining of the uterus is shedding so that a new one can be formed that would be ready, prepared if an egg were fertilized. Okay. And wanted to make a pregnancy and hormonally what's triggering that release of blood complicated. Mm-hmm. But we think it's the dropping level, especially the dropping level of estrogen. But for a long time, dropping progesterone has been seen to be the reason for starting to have flow. But you can have, and you do have perfectly regular 28 day cycles in which there's no progesterone made at all. So the decrease in estrogen is the driving force usually, but also I think there's a certain timing of the tissue of the lining of the uterus, the endometrium it starts to say enough already after about 28 days.

Mathilde:

And then a question that Belinda has, and also a lot of other, women probably have, what is it like normal bleeding and if the bleeding is more red or if it's more brown, what's considered normal?

Dr. Prior:

Okay. It's highly variable and it can vary within one person across the cycle. It also varies in the same person between cycles. So there's a lot of variability. And I guess this is as good a point as any to say. If you believe as I do that, the only way to find out what's expected or normal, I mean normal is pejorative for some people. Is to have a large longitudinal, randomly sampled population based study and the reality is we do not have those data. So we're working from imperfect evidence. Just remember that. And in fact, the dream that I have is, to do such a study. However, there does not seem to be the will nor the support at this point. So let me get back to the practical question. Flow is anywhere from a day or two to six or seven days, much longer than that is a concern. And how much bleeding that. So each soaked normal sized patter, tampon holds about a teaspoon of blood and it's normal to soak or, to use about 12. In a normal cycle, but if it gets to be much higher than that, it's too much. It's excess blood loss. Okay. Back to Belinda. Normally some people, and Belinda specifically gets cramps during her period. Mm-hmm. What are cramps and what's causing them? Okay. Cramps are the uterus contracting. They are a bit like the contractions that go with having a baby. Right. A lot of the same mechanisms, or as a friend of mine who had extremely bad cramps said, it's like your uterus having a heart attack.

Mathilde:

I like that.

Dr. Prior:

That's actually, yeah. Okay. So the purpose, if you, if you think about it that way, is to make sure that the lining is completely shed, so, like it's a physical mechanism mm-hmm. To get rid of the blood. Mm-hmm. And, and that is managed by another, a fatty acid kind of hormone called prostaglandin. Now what's good news is that prostaglandin production by the lining of the uterus and the muscle, the muscle is, what contracts is inhibited by an over the counter pill called ibuprofen, or those of the same chemistry, right? Nonsteroidal anti-inflammatory. Therefore, that's a specific treatment for menstrual cramps. Now, the problem is that if you take two initially, the first hint of cramps, and then you take another 200 milligram pill as every four hours, about half of women do not have effective control of their cramps. Mm-hmm. Right? And that is a pharmacologic. Issue. Mm-hmm. It, it should be solved. And we're currently doing a randomized controlled trial to test whether there's a better way of taking ibuprofen.

Mathilde:

Interesting. 'cause I have friends that have been prescribed to take ibuprofen and it did not work at

Dr. Prior:

all. Mm-hmm. So

Mathilde:

now they're taking stronger medication, I think the same ibuprofen, but in a stronger dose. Okay. to help with cramps, but still, sometimes it

Dr. Prior:

it, it needs to be something because cramps are so universal. Almost every young woman has cramps and they vary from cycle to cycle. In fact, the, the understanding that's in the general specialist literature is that you only get cramps if you've made an egg, if you ovulate it in that cycle. Mm-hmm. Okay. But that doesn't make a lot of sense since cramps are worse in teenagers who don't always ovulate. Mm-hmm. And they're worse in perimenopause when ovulation is becoming ragged or absent.

Sabrina:

Hmm. Yeah. There might

Dr. Prior:

be something else that we haven't figured out yet involved. Actually, we did a study and they are worse in anovulatory cycles. They're more common in ovulatory cycles, but they're more, more intense pain and duration in anovulatory cycles. Interesting. Another question is that people often feel tired Belinda

Mathilde:

might feel

Dr. Prior:

tired.

Mathilde:

And then they don't wanna exercise or they don't wanna do anything.

Dr. Prior:

well the tiredness is, you know, don't beat yourself up if you feel tired, but if you go for a walk, it's likely to help the cramps. Yeah. I always found that I never wanted to exercise during my period, especially in high school, but whenever I had to do, like I had a game or something mm-hmm. That I had to go to, I often felt

Mathilde:

better after. Is

Dr. Prior:

Is there any science that should suggest that? There is a lot that suggests it, that most pain is better if, you exercise. Okay. Whether we don't know the mechanism, whether it's distraction Yeah. Or whether there's something about brain activation. It's not clear. Okay. What I wanna mention before we get out away from the period is that. Most people don't realize that estrogen as well as progesterone levels are low during the first few days of the cycle. So if you are asked to have a blood test related to estrogen, for example, don't take it in the first eight days of your cycle. 'cause it's not gonna show anything relevant to your normal. No, no. You, the results will come back this woman's menopausal or something.

Mathilde:

Right. Yeah,

Dr. Prior:

that's good advice. It's

Mathilde:

so now we talked about the start of the bleeding. The first few days we're tired, we don't wanna exercise. And then we go into more day three to five. So at the end of your period or the end of Belinda's period, and as the period ends, what hormonal changes happens in Belinda's body?

Dr. Prior:

Okay. Basically estrogen's starting to rise. So it goes from low o over about 10 to 14 days to 200% higher.

Mathilde:

Mm-hmm.

Dr. Prior:

So there is quite a rapid increase. And what's happening is that, first of all, there were a whole bunch of follicles that were sort of called out from the ovary and said, this is your time, but one of those becomes dominant, and that dominant follicle starts making more and more and more

Mathilde:

Mm-hmm. Okay. So then we have the start of the follicular phase.

Dr. Prior:

phase. No, the follicular phase actually begins with the first day of the period. Oh,

Mathilde:

mm. Okay. So the

Dr. Prior:

follicular phase starts at the very beginning day one of when you start bleeding. Mm-hmm. Okay. And when this estrogen starts to increase, is it typical to also see increases in energy or that tiredness fading away? Or is that, no, I think tiredness mostly relates to the cramps.

Mathilde:

Okay, now Belinda is not on her period anymore. Yay. It's day six to day nine. So it's still early follicular phase. And then what's happening now that she doesn't have her period anymore? So hormonally, is estrogen still? High

Dr. Prior:

rising. Okay. And the dominant follicle is getting bigger and bigger. It's the, it's got two layers. The one layer makes estrogen. The other layer surprisingly makes testosterone, and testosterone gets made into estrogen. So in a way, the follicle that makes more testosterone becomes the dominant one, is kind of peculiar. Yes. Okay. At this point, some people say that their skin feels like it's glowing. I don't personally feel this, but Belinda does. Do the hormonal changes that you've just mentioned, explain why some people's skin might clear up.

Mathilde:

up.

Dr. Prior:

Well, as estrogen levels rise, there is less free testosterone, which acts on the skin. It, you know, gives pimples and things. Okay, so it can make sense. Yeah.

Mathilde:

So now we're at day 10 to 13, so more of a late follicular phase, and Belinda starts feeling really good. She's more happy. She has a higher libido, so a higher sex drive, but she doesn't know. Why is that? Could you explain hormonally what's happening?

Dr. Prior:

think culturally she expects to,

Mathilde:

Mm. S

Dr. Prior:

We did a study with women who were collecting a diary every writing down in the diary every day. And interest in sex was one of the things that they wrote about. And we knew also. Whether they were ovulating or not. And 53 women collected evidence over a mean of 13 cycles each. And we looked, we lined up all the cycles based on their day of ovulation, and we looked at interest in sex and plotted it across, and there was absolutely no blip.

Mathilde:

Oh. Hmm.

Dr. Prior:

Have other studies suggested this, or is it just like a cultural thing that we think we're getting close to ovulation? It's cultural. Yeah. Mm-hmm. Interesting. I mean, animal studies clearly show mm-hmm. That's the case.

Mathilde:

Just

Dr. Prior:

assume that would be the same. But women don't go around, you know, presenting their rum to, you know, their partner. I mean, this is bizarre. Women's sexuality is much more complex. And when we ask, using all of the information in the diary. What was related to interest in sex? It was self-worth and feeling of energy.

Mathilde:

That

Dr. Prior:

makes sense. I mean, you certainly, when you're tired on your period, you might certainly be less interested in it and then the rest of the

Mathilde:

per chance.

Dr. Prior:

it's just a little higher

Mathilde:

but it's,

Dr. Prior:

then there's so many other factors. Yeah. Mm-hmm. I think

Mathilde:

different for every woman. 'cause I know some women are, have higher libido during their period and

Dr. Prior:

Mm-hmm. Mm-hmm.

Mathilde:

not during their period. That's right. So it's

Dr. Prior:

too simplistic to say that it might

Mathilde:

peak at one point during the cycle

Dr. Prior:

It's, that's, that's exactly right.

Mathilde:

Okay.

Dr. Prior:

Good clarification. Mm-hmm. We're not driven by our hormones. Yeah. No,

Mathilde:

I think that's true.

Dr. Prior:

Okay, moving on. Day 14, average time for culation. First of all, what is ovulation? It simply means that that follicle is getting pretty big, an inch or so across just pops and literally the, the fluid and the egg go out into the peritoneum and get grabbed up by the fibrillated ends of the tubes. Interesting. Kate, this is something that I never fully understood until recently and I, I'm in women's health that the egg leaves. S the ovary doesn't just go straight in my mind, it's like a water slide right into the fallopian tube. But no, no, as you just explained here, it goes out into the ker. I don't, which just kind of like open space. Don't think we quite know how, how the, the tube finds the egg. Yes. It's so interesting. The egg doesn't have any propulsion system in it. It's not rocket propelled like a sperm is, you know? So ovulation, the assumption is it happens on day 14, and the assumption is that the luteal phase length is fixed at 14 days. However, and actually part of that is that the follicular phase is variable, but in reality both the follicular phase and the luteal phase are variable and. Ovulation is not inevitable, even if the cycle is perfectly 28 days and regular. So you cannot assume ovulation based on a regular cycle, and you can't use cycle day counting in a scientific study to document in quotes, ovulation.

Mathilde:

And let's say you're at home and you don't wanna get pregnant, so you look at your cycle and then your app is telling you at day 14 or 15, you're ovulating. So then you try to protect yourself or not have sex during these two days. Or the opposite if you're trying

Dr. Prior:

to get pregnant. Mm-hmm.

Mathilde:

Yes. Or if you're trying to get pregnant. Do you think that's a good way to do it?

Dr. Prior:

I would be very cautious about apps because in general, their way of figuring things out. I haven't been validated. I mean, they're black boxes. This is, you know, a, a profit making entity in most instances.

Sabrina:

How about, how about the whole taking of your temperature? Do you think that that's a reliable method? It's, a very science-based method because, do you know why not really?

Mathilde:

No.

Dr. Prior:

Progesterone raises the core temperature through some, some. Receptors in the brain, the pre-op cortex of the brain. So it raises the core temperature. Not a lot, but enough. That's measurable. So 0.2, 0.3 degrees Celsius. But the problem is that most methods of assessing where does the temperature start to go up? Where does it go up? Where is ovulation are not quantitative. They're unreliable. Different experts give different answers. So one of the things we did very early was to develop a quantitative way of looking at the temperature. Now, that was a fancy way and we validated it happily. We also validated a very simple way, which is, I mean, it does require some math. You just take all of the temperatures in one cycle from day one until the day before the next period and add them all up. Divide by the number of days. So you get a mean, an average, and then you can just look across the row of temperatures and say it goes above that average and it stays above that average. If it does that, that is the luteal face and the duration, how long it stays above that average tells you how much Perone has been produced. So you need a certain amount of progesterone for an egg to implant. So that, explanation and that way of evaluating basal temperature is on the emcor website. It's free for anyone to use.

Mathilde:

Mm. We'll add it in the

Dr. Prior:

and we validated it.

Mathilde:

Okay. And do you need to take the temperature at the same time of day? Absolutely.

Dr. Prior:

First thing when you wake up.

Mathilde:

Okay. In the morning.

Dr. Prior:

Another question is that some people and Belinda feel like she can actually feel when her ovulation is occurring. Is this real or is it kind of just

Mathilde:

think

Dr. Prior:

it's happening? Is there any evidence to suggest you? About 17% of the time, women will get something that feels like a cramp, but on one side or the other, and that is somehow associated with ovulation. I thought previously it was because the peritoneum was irritated by the blood and the fluid that, you know, suddenly spills into it. But it may be some cramping in the ovary just before the egg is released. Okay. So some people might feel it, but not everyone. Some people might feel it and. You might feel it some cycles and not others. Right. And always ask yourself, could this be a gut thing? Because it's all, it's all confusing because the gut is gurgling around and doing strange things all the

Mathilde:

time. That's a good point.

Dr. Prior:

Okay. So don't rely on it. If you don't get that feeling, don't say you didn't ovulate. Right.

Mathilde:

right?

Dr. Prior:

Unfortunately, we don't feel different if we ovulate or not. Okay. Which, is a problem.

Mathilde:

Why is it a problem if we don't ovulate?

Dr. Prior:

Ah, it's a problem if you don't ovulate because you need progesterone to counterbalance that growth stimulating effect of estrogen. They're part of a system. You're missing half the system. But the common problem is not, not ovulating. The common problem is ovulating with a too short luteal phase, which is the time from that ovulation till the next flow.

Mathilde:

Okay? Mm-hmm. So it's

Dr. Prior:

often too short. Mm-hmm. It's problematic. That usually means that the person is responding to some kind of stressor. It could be a food stressor, it could be a sleep stressor, it could be an emotional one, and stressors are common. Yeah.

Mathilde:

And are there any tests that you can do to see if you're ovulating? Because I've heard that sometimes you can have your period, but you're not necessarily ovulating. That's right. And then you can also maybe not have your period and be ovulating

Dr. Prior:

Mm-hmm. You got pregnant.

Mathilde:

Yeah. It's very confusing and also scary for a lot of women that maybe wanna get pregnant one day.

Speaker 2:

day.

Dr. Prior:

Mm-hmm. Mm-hmm. Okay. It's complicated. And in a way, it's really complicated today because of, quite rightly, the Canadian Institutes for Health Research and the National Institute of Health in the United States started saying, you have to study young women. Heck with this deal of studying just men. But they didn't tell the researchers how to study young women. So there's a lot of, pardon my French crap in the literature now. Not appropriately, they're saying that women are atory without actually proving it.

Mathilde:

I know that on Amazon they sell a revelation test. I don't know if that's reliable,

Dr. Prior:

but I think if you're not trying to get pregnant, I think using the quantitative basal temperature and keeping track of cervical mucus is sufficient.

Mathilde:

So now we're at day 15, so right after ovulation that mm-hmm. Or Belinda's ovulation. So day 15 to day 18. So it's the early luteal phase. Mm-hmm. So what's happening here? I know you mentioned maybe progesterone is higher. Mm-hmm.

Dr. Prior:

What's amazing is that. Remember this ring of of cells that pops open and allows the egg to go out. Now some of those cells are left in the edge of the ovary and it changes to start making progesterone, and how it does that is not entirely clear because it wasn't making progesterone before. They were not. We are making estrogen or testosterone, so it takes a bit of time to ramp up production, but when progesterone starts going up, it's been low through the whole follicular phase. When it starts going up, it doesn't stop at 200, like estrogen, it goes up to 1400. There's a massive amount of progesterone made, which is why I think it's so important. Because the body doesn't just make steroid hormones for the fun of it.

Mathilde:

and that progesterone is made when the egg is

Dr. Prior:

Mm-hmm. It's not made before that.

Mathilde:

And if someone is not ovulating, then there's no progesterone.

Dr. Prior:

That's right. Well, that's not quite true. There's a low level of progesterone and children, men, women, and that comes from the adrenal.

Mathilde:

Mm-hmm.

Dr. Prior:

Okay. Now, Belinda also says she feels tired during this phase. Is that explained hormonally? No maybe just there's a lot. Well, we tended as women to need to figure out why we're feeling the way we're feeling. And there's been a lot of what's called attribution. And it's easy to say it's my hormones, and it's particularly easy to say it's because progesterone is making me feel bad, and that really doesn't bear out. Out. Does there any explanation as to why some people might feel like mood swings or changes as they get to that period of the menstrual cycle? There is progesterone increases, I think, perception

Mathilde:

sensitivity,

Dr. Prior:

you will,

Mathilde:

of

Dr. Prior:

every sort. So you can either go with it or you can try to be very efficient and keep that away. But if you are open to it, you can then perceive things in a new way. You can be more, mindful or thoughtful or whatever. You can sense emotions with better perception, with better, precision than you might before. And is that progestin

Mathilde:

acting on a different.

Dr. Prior:

part of your body, like your brain or something? Mm-hmm. Okay. We don't really understand it. And almost all the emotion, mood, brain literature is biased in favor of estrogen.

Mathilde:

Yeah. Estrogen is seen as the happy hormone. From what I'm seeing online is just when you have a lot of estrogen is when you're happy and when you don't is when you're like,

Dr. Prior:

no. Reality to that. Okay. That's expectation.

Speaker 2:

Okay.

Dr. Prior:

Next phase would be the late luteal phase. So around like day, night, whatever that is, whatever that is. It's blame for everything. What's happening hormonally here? Any big changes to note estrogen and progesterone if you've ovulated are starting to drop. Okay.

Mathilde:

Both of them.

Dr. Prior:

Mm-hmm.

Mathilde:

Okay. And then Belinda is starting to have more skin breaks out.

Dr. Prior:

Okay.

Mathilde:

related to hormones

Dr. Prior:

Well, again, because when estrogen is high, there's more sex hormone binding globulin, less of the testosterone is active. So you might get more breakouts then.

Mathilde:

That's interesting. 'cause I saw a lot of people blaming testosterone and breakouts, but

Dr. Prior:

Well, testosterone is associated with acne for sure. But what proportion of testosterone is active depends on how high the estrogen is.

Mathilde:

Yeah. So maybe your one pimple when you're on your period is not from Oh yeah. I get one pimple always in the same

Dr. Prior:

spot

Mathilde:

right before

Dr. Prior:

my

Mathilde:

period

Sabrina:

And

Dr. Prior:

we're like, there's gotta

Mathilde:

be something to explain that

Dr. Prior:

I It happening every day. Yes. I, yes. And. And That area is where the guys start getting hair first. Hmm. So there is a hormonally, there must be something about that anatomy that in the upper lip.

Mathilde:

right? Mm-hmm. And,

Dr. Prior:

and as older women or as people on androgen ablation therapy start losing that hormone, this is the last to go.

Mathilde:

Interesting.

Dr. Prior:

There's something hormonally differently. Mm-hmm. Not part of the phase. There's an anatomy thing. Yep. Okay.

Mathilde:

So now we're in the premenstrual phase for Belinda. So day 23 to 25 and Belinda starts feeling more bloated during that time.

Dr. Prior:

Mm-hmm.

Mathilde:

Was, would there be a link with her menstrual cycle coming

Dr. Prior:

up? That's a very, very interesting question because I. In the same diary that I mentioned before, we ask about, fluid retention is the way we put it it and we did the study. What day of the cycle do you think is maximal for fluid retention? Any guesses? I

Mathilde:

I would say like first day of your period, maybe.

Dr. Prior:

My God. You got it. Oh, I was gonna say

Mathilde:

too. That's

Dr. Prior:

one. I'm middle thirsty.

Mathilde:

Me too. Does that

Dr. Prior:

make sense? Mm-hmm. It's actually what we found. Okay. It's because you're about to deplete a bunch of fluids. Oh, maybe but I think it has to do with the duration of estrogen exposure. The thing that I had the most trouble with when I took that estrogen only part of the birth control pill was that I blew up like a balloon. And, I mean, I literally couldn't get my feet into sandals much as shoes. And got migraine. And my personality was clearly changed. So I think, there are estrogen effects on the fluid system that most times we don't realize, but I think it's a duration effect. Okay. And she starts having PMS and she starts arguing with her boyfriend. Yes. And she starts picking on other people and,

Mathilde:

Yeah, exactly. What are PMS and are they

Dr. Prior:

alright?

Mathilde:

in

Dr. Prior:

Again, I think if the person is ovulating, I think it's that increased sensitivity and the tendency to now blame all the things that you've sort of not dealt with before. Your kids stuff, or your money stuff, or your work stuff, whatever it is that, was difficult to deal with now suddenly you can't avoid it anymore. Again, I don't think it's a negative effect of hormones. I think it's a natural human tendency to put off dealing with stuff, and then you can't anymore at that point, and it just is right in your face. I used to tell patients, like I told myself, which is to say to those around, you don't, it's not your fault, I'm just feeling kind of out of it or unhappy or whatever, bitchy today,

Mathilde:

I always

Dr. Prior:

have to say that to my partner. Mm-hmm. I get really irritable mm-hmm. Before my periods. It's like everything

Mathilde:

I could do

Dr. Prior:

before and just be okay with it is really frustrating for me. Mm-hmm. See it. And I'm just like, guys,

Mathilde:

just gimme a minute.

Dr. Prior:

We'll, through this soon. Do you think that'd be a common experience? And don't take it and don't take it personally? Yeah. I'm trying hard not to take it out on you. Yeah. But I'm just feeling this way.

Mathilde:

Totally. And crying is also a big thing for me. More than normally I guess. And yeah, I cry really easily.

Dr. Prior:

Well, that sensitivity is important. And it's one of the strengths of women. If we can recognize and deal with that increased sensitivity, the world would be a lot better place. And just so I understand

Mathilde:

your

Dr. Prior:

thought, your thinking is that it has to do with that increase in progesterone, but it's not clear how it's acting on the brain? Or is that mm-hmm. No, because progesterone and estrogen are both dropping during that time. Oh, okay. So hormonally, what do we think is happening to increase that sensitivity? You've been exposed to estrogen for a longer time. You've been exposed to progesterone. So the sensitivity is there. The irritability, I would attribute to estrogen, actually the dropping levels probably also provoke some changes in the brain. We know that for big drops, right. But for example, I said before that steady estrogen prevented bone resorption, but dropping estrogen increases it. So there's enough drop from the high at mid cycle to the low during flow. That there's increased bone resorption at that point in the cycle. So maybe it's having effects. Somehow in our brain we just completely understand the That's right. Okay. Very

Mathilde:

Very interesting.

Dr. Prior:

I think that was a good summary of the cycle. I talked about a lot of

Mathilde:

stuff,

Dr. Prior:

but we wanted to play a fun game that's also about Belinda. It's called Belinda's Brilliance, or Be Below Me. 'cause our hypothetical, Belinda goes through life and hears sources say lots of different things about hormone health. Mm-hmm. And the menstrual cycle. So it's essentially true or false. But we're gonna give you some statements, Belinda might have said,

Mathilde:

and then we want you to tell

Dr. Prior:

Us if they're baloney or they're brilliance. Okay. Okay. First one. When someone's taking hormonal birth control, their body stops producing sex hormones pretty close to. Brilliant. Pretty close. Okay. Can you elaborate? Yeah. It's a huge effective suppressor at the hypothalamic level.

Mathilde:

And then another thing that, the Linda thinks is right, is being on hormonal birth control stops you from cycling naturally.

Dr. Prior:

That's also brilliant. You might still get your period, but it's because of the ups and downs of the hormones you're taking and not the hormones that you're making in your body. Does it depend on the type of hormonal birth control that you're on? Yes. For example, progestin only birth control, you can have irregular cycling. In fact, no particular cycle, just bleeding whenever, which is one of the disadvantages of it.

Mathilde:

Okay.

Sabrina:

Next

Mathilde:

one

Dr. Prior:

from Belinda. You can get pregnant when you're on your period. Mm. Pretty much baloney.

Mathilde:

Okay. The next one is, it is normal to have debilitating menstrual cramps making you unable to do much during your period. Bologna. Mm.

Dr. Prior:

Most normal, most women have some cramps. Ibuprofen should take care of it. If this is, you're listening in the. Okay. In the fall and early spring of 2025 and 26, we're doing a randomized controlled trial right now That was our round of Berlin and baloney. Thank you for playing along. You're welcome. That was fun.

Speaker 2:

fun.

Mathilde:

So now we're gonna move on to our section that we have in all episode, which is what women really wanna know. Mm-hmm. So our audience ask questions before this interview, for you. I just wanna make a quick note that we received a lot of questions, so that's really great. I think. People that are listening have a lot of questions in general about this specific topic. I think we are seeing a lot of things online and right now there's also a

Dr. Prior:

there's a lot of bologna.

Mathilde:

Yeah. A lot. We're, we're seeing a lot of baloney. Yeah. Yeah. Yeah. And, I just wanna mention before we go into the questions that we received a lot of questions specific on birth control or PCOS or endometriosis. But we're gonna have episodes that are focusing only on this as it is very, important topics, but also very complex. And then we also received a lot of, questions about nutrition and what are the power foods, things like that. And then we're gonna do an episode on that,, as well.

Dr. Prior:

your questions have not been forgotten. Yeah. But they won't be in this episode. So

Mathilde:

first question that we have for you, Dr. Fryer, is my A DHD medication seems to work differently depending on my cycle. Is that real or is that just In my head, it's

Dr. Prior:

it's likely real.

Mathilde:

Oh,

Dr. Prior:

And, and it's been almost never studied. So it's an important area of research, but it's all hormonal. So it's not unsurprising that they could be interacting in some, not at all. Surprising. Okay. Just ignored. Yes. And not ever studied, like all these things in Moment Health. Yeah. Okay. So. You're probably not

Mathilde:

crazy.

Sabrina:

Exactly.

Dr. Prior:

Exactly. Okay. Our next question from our audience is, if someone has a hormonal imbalance that doesn't get treated, what are the kinds of long-term effects that could have on their house? It's a big question. It's a very big question. Question. What I about is that if a quarter of the most healthy women during the year have short luteal phases or anovulation, what we know is that they are losing spinal bone density. That's just one example. Mm-hmm.

Mathilde:

I

Dr. Prior:

think that we need to be documenting ovulation in order to understand health, not just fertility, which means that we need a way of doing it that's very simple for the people who. Really are not organized enough to take their morning temperature every day and write it down,

Mathilde:

Right?

Dr. Prior:

And I've been working hard. I have a good idea for something that could be tested once a cycle that would tell that about the previous cycle and just have not been able to get funding. That sucks. Mm-hmm. That'd be great. Mm-hmm. Yeah, because I think that that's such an interesting point is that we often think about ovulation in terms of reproduction, but as we've discussed a lot today, it's important for your

Mathilde:

health as well. Absolutely.

Dr. Prior:

And we need to start thinking about that as well in these conversations.

Mathilde:

Yeah. Okay. The last question that we have from our audience is someone that is asking if there's a specific type of birth control that can help with hormonal acne

Dr. Prior:

yeah. Now there is, all the choices of progestins, the progesterone, like chemicals that are manmade. There's one called Sperone, which acts as an anti-androgen. Okay.

Sabrina:

Okay.

Dr. Prior:

And therefore that would be a better one probably for someone with acne.

Mathilde:

And that's only progestins in it.

Dr. Prior:

it. It's only the progeta? Well, it's with estrogen, of course. Oh, okay. Has to be with estrogen in order to prevent pregnancy.

Mathilde:

Right. Okay. Okay.

Dr. Prior:

That's good advice. So someone could take that to their doctor and maybe ask mm-hmm. Does this one have progestin in it? Because most of the progestins that we have still are derived from testosterone. So they have some intrinsic male. Hormone type characteristics.

Mathilde:

Mm-hmm. I heard that they are now developing new hormonal birth control pills that are more specific to the actual real hormones and not just synthetic estradiol. Or there

Sabrina:

They're

Dr. Prior:

now is a pill that has 17 beta estradiol in

Mathilde:

only in the states. And not accepted in

Dr. Prior:

yeah. I don't know. I don't think it's here, and I'm not sure I heard about it in Europe about 10 years ago, but I haven't. Yeah. Yeah. yeah.

Mathilde:

I have

Dr. Prior:

a question.

Mathilde:

That's

Dr. Prior:

My submission to the, what women wanna know. And I don't know if there is an answer for it, but I'd love to hear your thoughts. Mm-hmm. We discussed before this episode that in our experience it seems as though young

Mathilde:

nowadays experience a lot more pain with

Dr. Prior:

their menstrual cycles than in our, our Mother's Day, for example. Or at least that's what they've reflected to us. Have you seen that in practice and do you think it it's, that's true,. Or do you think it just, it's being studied more than now than it was before? I really don't know because women, my generation and my mom's generation we're just basically told to suck it up,

Mathilde:

Right.

Dr. Prior:

Mm-hmm. So maybe it was, it was still happening, just like all these other things. They didn't dare talk to the doctor about it. I mean, that would be silly. Right, right. Yeah. So it's hard to know.

Mathilde:

Mm-hmm.

Dr. Prior:

Okay. That's totally a fair answer. Okay. We have a couple wrap up questions. These are kind of big questions, but we would like to know, first of all, if you could bust one myth about women's health forever, what would it be? That estrogen is the most important hormone. Because it's estrogen and progesterone forever. You know, it's the two together, they're in a tango. Mm-hmm. And estrogen promotes growth. Continually. Progesterone's job is to cause the cells to become more specialized or differentiated and to slow the growth of estrogen. So they work together.

Mathilde:

One other question is, what's one change you hope to see in women's health in the next 10 years?

Dr. Prior:

I hope there'll be a single once a cycle test during flow that will tell a woman whether she ovulated and whether it was normal ovulation or not.

Mathilde:

Okay. Because there's not normal relation to

Dr. Prior:

We don't have such a test. Okay.

Mathilde:

You

Dr. Prior:

know, I don't think I ovulated until I was 25 or 26. I was just stressed. I was trying to go to medical school and they didn't want girls.

Mathilde:

Mm.

Dr. Prior:

Right. All right. Well that's all of our questions

Mathilde:

today. Yeah. Thank you so much for sitting, sitting down

Dr. Prior:

with us answering. We went through a lot of things today, so it's an amazing system and it's producing good health. Yeah. Think of it that way, that rather than producing BMS or something

Mathilde:

Mm-hmm.

Dr. Prior:

If there's someone doing interesting and you think reasonable research in women's health, volunteer and get your friends to volunteer. Do you have a spot where people can look for participation in research, or at least with

Mathilde:

you're doing?

Dr. Prior:

There's reach bc mm-hmm. Which has outline of all kinds of studies that were being done around the province. And there's also, women's Health Research Institute website.

Mathilde:

Okay.

Dr. Prior:

Go look there. You wanna be part of artist?

Speaker 2:

six?

Mathilde:

We'll put all the links under the episode. Okay. Well, thank you so much. Thank you.

Dr. Prior:

You're welcome.