The Ovary’s Side of the Story: Menstrual Cycle Myths Explained

Most people think of the menstrual cycle as bleeding, cramps, cycle day one, or an app prediction. But the period is really the final report — not the main event.

In this episode of Taco Bout Fertility Tuesday, Dr. Mark Amols explains the menstrual cycle from the ovary’s point of view. Learn how the brain, ovary, and uterus communicate each month, why one follicle becomes dominant, why IVF does not “use up” future eggs, and why so many common menstrual-cycle myths fall apart once you understand the science.

We cover myths like whether ovaries take turns, whether one ovary means ovulating every other month, whether bleeding always means ovulation, whether cycle apps really know when you ovulate, and whether everyone needs to wait three months after a miscarriage before trying again.

The menstrual cycle is not a calendar, an app prediction, or a right-left ovary schedule. It is a hormone conversation between the brain, ovary, and uterus.

Thanks for tuning in to another episode of 'Taco Bout Fertility Tuesday' with Dr. Mark Amols. If you found this episode insightful, please share it with friends and family who might benefit from our discussion. Remember, your feedback is invaluable to us – leave us a review on Apple Podcasts, Spotify, or your preferred listening platform.

Stay connected with us for updates and fertility tips – follow us on Facebook. For more resources and information, visit our website at www.NewDirectionFertility.com.

Have a question or a topic you'd like us to cover? We'd love to hear from you! Reach out to us at TBFT@NewDirectionFertility.com.

Join us next Tuesday for more discussions on fertility, where we blend medical expertise with a touch of humor to make complex topics accessible and engaging. Until then, keep the conversation going and remember: understanding your fertility is a journey we're on together.

Transcript

>> Dr. Mark Amols: 0:00

Today we talk about the menstrual cycle from the view of the ovary's perspective. I'm Dr. Mark Amols, and this is Taco Bout Fertility Tuesday. Back in 2024, I did the podcast episode on the menstrual cycle, but this time it's going to be a little different. Last time, we talked about the follicular phase, ovulation, the luteal phase, progesterone, and basically why a period happens. But today, I want to come at it from a different angle. Most people think of the menstrual cycle as

a period: 0:45

bleeding, cramping, cycle day one, when the next period is basically due. But the period isn't the main event. It's the ending. It's the visible part. The thing you notice, the real story starts earlier. It starts with the brain talking to the ovary, the ovary growing follicles, the follicles making hormones, and the uterus responding to those hormones. So instead of looking at the cycle from the calendar point of view or the app point of view, or the day 14 must mean I'm ovulating point of view. We're going to look at it from the ovary's point of view. Because once you understand what the ovary is actually doing, a lot of myths fall apart. Myths like the ovary takes turns every month. Or if you only have one ovary, you only ovulate every other month. Or a period means you definitely ovulated. Or that a regular period means everything's fine with fertility. Or that pregnancy symptoms before a test mean you must be pregnant. Or that after a miscarriage, you must wait three months before you try again because you have to let the uterus repair itself. They all sound logical, but almost none of them hold up. There are three players in the menstrual cycle. The brain, the ovary, and the uterus. The brain is the signal sender. The hypothalamus and pituitary release two hormones that we care about called FSH and LH. FSH stands for follicle-stimulating hormone. It stimulates the follicles to grow exactly like it sounds. LH LH, luteinizing hormone, becomes important later at ovulation and afterwards. Now, the ovary is where the follicles live, and the eggs are inside of the follicles. The, ovary isn't sitting around waiting for the calendar to tell it, hey, it's time to ovulate. It's responding to the hormonal signals, the FSH and LH. The uterus does not control the cycle. It's actually responding to the cycle. Essentially, it's the end organ. It builds a lining under estrogen production that occurs from the follicles growing, and then that lining matures under progesterone that develops after ovulation, with LH helping progesterone continue to be made, and then it sheds if you are not pregnant. So the point is this. The uterus is not running the show. It's just reporting what's happening. Essentially, a menstrual cycle having a period isn't the uterus just randomly deciding to bleed. It's the result of a hormonal withdrawal when the progesterone drops after ovulation because you didn't get pregnant. So essentially, the menstrual cycle is a conversation. The brain sends a signal, the ovary responds and makes hormones, the uterus responds to those hormones, and the period is the final report. Now, when we think of the follicles growing every month, we think of it kind of like the strongest one makes it. But that's not exactly the story. It's more like a race. See, at the start of the cycle, estrogen and progesterone are low, usually right after the corpus luteum has failed by collapsing and progesterone has dropped. When the brain senses this, it then tells the pituitary to release FSH. Now, FSH doesn't just go to one ovary. It circulates through the bloodstream to both ovaries. And then inside each ovary, small follicles capable of responding will then start to grow. When the FSH starts rising, this is the race. So FSH is the starting gun. Several follicles start taking off. They start growing and producing estrogen. Now, early on, more than one looks like it has a shot. But then something interesting starts to happen. The rising estrogen tells the brain, hey, we have enough follicle activity. You don't need to keep making FSH. So FSH starts to fall. That drop is the key moment. See, these smaller follicles are completely dependent on the FSH to keep growing. So when FSH starts falling, they lose support, and then they undergo atresia, which is basically a way of saying they're dying. One follicle keeps growing. This is the dominant follicle. This follicle doesn't need high FSH to keep growing. So essentially, this isn't the body interviewing eggs for the best resume. It's more mechanical than that. The dominant follicle is simply the one that became most capable of surviving in the new hormone environment with lower FSH. Essentially, the biology is the follicle that becomes the dominant one has more FSH receptor activity, better granulosa cell function and stronger estrogen production. Basically, it's more efficient with the fuel that's left around because the smaller follicles need much more fuel to grow. They can't keep up. So it's a race where the fuel supply gets cut in half. Halfway through the growth, the runners that need a lot of fuel drop out, and the one that learned to run on less fuel keeps going. But the dominant follicle doesn't just win, it changes the entire race. As it grows, it produces estrogen and inhibin B, which suppresses FSH even further, making it even harder for the small follicles to keep up. This is why in IVF and other treatment cycles, we give you FSH because we know naturally it will drop. By us continuing to give you the hormone, we can keep those smaller follicles growing. Essentially, these large dominant follicles become the ovarian villain. Even though they're winning, they try to make it harder on the other ones. But the other part is it starts to become more responsive to LH and this is needed to support the final stretch to ovulation. This is the reason why in nature you only make one follicle every month. Dominance isn't about being chosen, it's about surviving. When the FSH falls. To prevent this lead follicle from dominating in IVF, we give FSH at high doses and keep pushing it, not letting the smaller follicles fall out of the race. So we rescue them. But it's important to understand, IVF isn't creating eggs from nowhere, it's rescuing the follicles that would have normally died that month. And this is important because when you think about, well, am I losing more eggs when I do IVF? Because now we're making them ovulate, the answer is no. These were the eggs that were going to die anyway. And in the same token, when people say, well, will giving more meds make more eggs? Technically, no. You can only make the eggs grow that were going to grow. You're just taking those follicles that would have been selected out and making them grow. One myth that I hear a lot of times is that the ovaries take turns when you ovulate. A lot of people believe this, that one month the right ovary goes, the next month the left and back and forth. That's a really neat idea. It's quite organized and fair, but it's also not true. There is no ovarian custody schedule. As I mentioned earlier, the FSH travels through the entire body in the bloodstream. It goes to both ovaries. It doesn't just go to one or the other. So whichever follicle is in the lead and is dominant is the one that's going to ovulate, whether that's right, left, same side twice in a row, or no pattern at all. It's going to look random because it is random. But let's look at the math for a second. Ovulation is kind of like a coin flip. Right is heads, left is tails. So what would be the chances of ovulating on the same side for a full year? That means 12 times flipping the quarter and landing heads 12 times in a row. It's about one in 2048. That doesn't seem very hard to believe it could happen, but not really that often. But what about five years, which is 60 ovulations? And what's the chance of that? Well, that's one in 576 quadrillion. Yeah, that's a really big number. Basically impossible. But let's go bigger. What about the same side for your entire reproductive life? One side always ovulating, never the other side. From age 12 to age 51, that's 468 ovulations always on the same side. Well, the number's so big, I'm just going to have to tell you it's 1 in 3.8 times 10 to the hundred and fortieth power. So that's basically outside of normal human conversation. That's a really big number. At that point, the universe has filed a complaint saying you are breaking all the laws. The point is, if someone says, hey, my right ovary ovulated every month for five years straight, either they're the ovarian lottery winner, or we need to check the ultrasound receipts for that, because it's very unlikely. But here's the interesting thing. Biology isn't perfect coin flips. Some studies actually do suggest the right ovary ovulates slightly more than the left. But even though that may be true, it still doesn't happen every single month for a year or even five years or longer. Another myth that kind of piggybacks on that is that if you only have one ovary, then you only ovulate every other month and you can only get pregnant every other month. But we talked about this. FSH and LH go everywhere in the bloodstream. It circulates to both ovaries. And even if you have one, then it gets all the hormones. Your ovary doesn't say, well, you know, I worked last month, so I'm going to be on PTO this month, I'll be back next month. It doesn't work that way. If you have one ovary, it will then ovulate every month, just like if you had two ovaries. And it's no different for guys. If they lose a testicle, their one testicle will keep making sperm. And, interestingly enough, the amount of sperm they make is still usually good enough. Now, there are some differences. When you're just trying to get pregnant, you still only need one egg per month, so it will go well. But if you need to do something like IVF now you're going to have a fixed total number of follicles because now you only have one ovary, and so you will make fewer eggs in the IVF cycle. But that's really talking about ovarian reserve, not ovulation frequency. That's a different thing. The point is, if you have one ovary, you will still have regular cycles and conceive naturally because every month you will ovulate. Another myth is that if you have a menses, then it means you ovulated. And that's a pretty fair thing to think because it's pretty much mostly true. But there are also women out there who do not ovulate and those follicles still make estrogen and they still build a thick lining. And even without ovulation even happening, because that lining thickens up, it starts to break down because it becomes unstable and you can have a period and that period can hormonally kind of line up every month. So for example, women with PCOS can experience this every month, getting what they think is a period, but actually are not ovulating. The best way to determine if you're ovulating is not even using LH strips because that can be elevated in people with PCOS. So usually doing a day 21 progesterone is going to be the best measure if you're ovulating. Here's another interesting myth. After a miscarriage, you should wait three months before trying again. Now, this is not completely true. Matter of fact, as soon as you have a menses, you can try again. That doesn't mean there aren't real reasons to wait, such as there can be issues like infections, retained tissue. There could be concerns that are going on. There might even be just emotional reasons that you want to wait. But the one thing that isn't true is that your body has to heal, because we've talked about that's not how the menstrual cycle works. When the endometrium sheds, the entire lining sheds, which means when it regenerates, it's a brand new lining. There isn't something that needs to heal. Your lining has healed by shedding, so you can absolutely get pregnant again. Think of it like grass. Just because you mow it doesn't mean it won't come back. And this isn't just my opinion. The American College of OB-GYN discussed this in a study saying that there is no reason to make people wait three months to be able to get pregnant again after a miscarriage unless it's medically necessary. The next myth I hear is that if you have a regular period, it means everything must be fine with your eggs. And yes, a regular period is reassuring, usually means ovulation is happening in a predictable pattern. That means the brain-ovary-uterine connection is working well. But it doesn't prove egg quality is normal. It doesn't prove that there are not other issues going on, such as with the sperm or the tubes. So, yes, a regular period is great, but what it doesn't tell you is whether your egg quality is good. And you should not rely on just having a regular period every month, meaning everything is fine. One of my other favorite myths is when people tell me, oh, no, I know I'm ovulating. My cycle app tells me that. But the problem is cycle apps are not watching your ovary. They're doing math. Most estimate it by looking at when your last period was. They figure out how long that cycle was, let's say 28 days. And then they subtract 14 days and say, okay, you're ovulating on the 14th day. And it's pretty accurate, especially if you have regular cycles and the app looks really smart. But the thing is, without real biological data, such as LH testing temperature shifts or hormone monitoring or even ultrasound, it doesn't really know anything. It's just guessing. So remember, it's a tool, but it's not really perfectly accurate. And I would not rely on it to know everything's going fine. If you're still not getting pregnant and you've been trying for some time, even if your app says everything's fine, still see your doctor. Another myth is if you feel pain on the side when you're ovulating, it must be the side you're ovulating on. And it's definitely a clue, but it is not foolproof. Pelvic pain can come from the rupture and the fluid released after ovulation. And that can irritate the other side and that can sometimes cause some discomfort, making you think you ovulate on one side, but really it was the other side, and that's because of what we call referred pain. Just because you feel the pain outside doesn't mean it's coming from there. there. It's kind of like symptoms of pregnancy. Just because you feel symptoms of pregnancy doesn't mean you are pregnant. You can end up having, for example, elevated progesterone due to a corpus luteal cyst that's making high progesterone levels. Now your breasts become tender, you start to feel pregnant. In reality, it's just progesterone because that's the pregnancy hormone. The symptoms are correct. They just happen to be from something else. And that's the problem. Symptoms can tease you and can make you think things are saying something they aren't. aren't. So how does all this connect then, to fertility treatment? Well, nearly everything we do in fertility treatment is built on this conversation. Cycle day one tells us the hormone system is resetting. Baseline ultrasounds tell us that the ovaries are quiet. There are no cysts making any hormones. Day three labs catch the estrogen and progesterone near the low point, while FSH tells us how hard the brain is working to recruit the follicles. At the beginning of the cycle, when it comes to Letrozole, also known as Femara and Clomid, they change the brain-ovary conversation. It causes more FSH to be released and that signal is stronger to the ovary, which then will cause more follicles to grow. When you give injectable medications for IUI, IVF, this is now bypassing the brain ovary connection and now it is directly recruiting more follicles by supporting the growth of those follicles that were going to drop out because there was not as much FSH. Essentially, taking meds like Gonal-F and Follistim is like DEI for follicles that were never going to make it. Now everybody gets a chance and it all ends then with the trigger shot. This is the LH that causes the final egg maturation and the timing of ovulation. Now, because LH isn't as stable, we use hCG, which mimics LH and that causes the ovulation. Now, if you're in a non-ovulatory treatment cycle, progesterone support, then afterwards gives the uterus what it needs to mature and hold the lining. Essentially, fertility treatment is us learning the ovarian schedule and then politely hijacking it. We're not fighting the menstrual cycle, we're using its own rules to our advantage. To recap, quick myth check before we go. Ovaries don't take turns. Whichever follicle wins that month's race ovulates. And the odds of a true alternating pattern are astronomically small. One ovary doesn't mean ovulating every other month. It can still ovulate every cycle, though the total egg supply may still be lower. Bleeding doesn't always mean you ovulate, and anovulatory cycles can still produce a period-like bleed. A regular period is reassuring but not a guarantee. It's one vital sign, not the whole fertility picture. Cycle apps are guesses, not ultrasounds. Useful but not proof of ovulation timing. And not every miscarriage requires a three-month wait. The endometrium is built to regenerate monthly. Once you understand the ovary side of the story, a lot of what you thought you knew about periods, ovulation and miscarriage timing starts to look different. The point is, the menstrual cycle isn't a calendar, isn't an app prediction, doesn't have a right-left schedule. It's a hormone conversation between the brain, the ovary and the uterus. Hopefully you like this episode. As I mentioned, in 2024 I did one on the menstrual cycle. If you want to understand more of just the menstrual cycle and the steps of it. If you like this episode, as always, tell your friends about us and give us a five-star review on your favorite medium. But most of all, if you love it, keep coming back and I look forward to talking again next week on Taco Bout Fertility Tuesday.