30 Myths About The Menstrual Cycle That Just Won’t Die

The menstrual cycle has been fascinating and baffling we humans since the beginning of time. Unlike any other fact of life, getting your period is at once a normal bodily function, a rite of passage, and historically, a fraught cultural event.

There actually aren’t a ton of mentions of menstruation throughout recorded history, probably because men were the ones in charge of writing things down. But for centuries, teachings from various world religions, including Judaism, Islam, and Christianity, have said that menstruation is both physically and spiritually unclean, forcing menstruating people to be isolated. In fact, the Hebrew word for “menstruating woman,” niddah, also translates to “expelled.”

Meanwhile, many cultures believed that menstrual blood is literally magic — the dark kind, mostly. For example, the ancient Roman scholar Pliny The Elder wrote that contact with period blood “turns new wine sour, crops touched by it become barren, grafts die, seed in gardens are dried up, the fruit of trees fall off...and a horrible smell fills the air; to taste it drives dogs mad and infects their bites with an incurable poison.” According to Cherokee teachings, menstrual blood was thought of as “a potent force possessing rare destructive capacity” that could be unleashed in sorcery rituals. It is considered so powerful a substance that the idea behind the isolation of menstruating women in Cherokee traditions is not cleanliness but safety.

And this is just a sampling of what history tells us about the myths surrounding the actual bleeding part. What about premenstrual syndrome (PMS)? And ovulation?

The point is, myths about the menstrual cycle are as essential to the human experience as the sunrise or the sunset. These myths have been around forever, and they continue today, albeit in less mystical forms. For example, many people still aren’t sure whether period sex can lead to pregnancy (it can) or even whether PMS is real or not (it is). The good news is that, unlike the intractable facts of the earth’s orbit, period myths are something we can actually change.

Ahead, a guide to the real truth about your menstrual cycle, once and for all.

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Myth: Period blood is gross.
As we mentioned, the actual blood part of the whole period thing seems to have been the source of some major misunderstandings throughout history. Today the myth persists that periods are “unclean” or should be hidden in some subtle, yet still annoyingly harmful ways. For instance, many women still feel the need to scurry into the bathroom at work so no one sees us holding a tampon, and plenty remain squeamish about directly mentioning the words “period” or “menstruation.”

These examples may seem harmless, but the reason it’s important to continuously fight back in our own minds against thinking of our periods as gross or shameful is because not freely talking about our periods with our friends and family can make it that much harder to talk to our doctors about them when something isn’t right. "Shame and stigma around periods from family or culture can impact the delay [in seeking help]," Arielle Dance, an endometriosis advocate, told Refinery29 in April. "Women are less likely to seek help for discomfort when their family never talks about periods." Also: It’s just a waste of time to stress or feel the need to hide the fact that you, too, have a normal human experience every month.
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Myth: Period blood is just regular blood.
While Pliny the Elder may have been wrong that having your period will ruin your wine-drinking (dear God, no), he and all the other historic dudes who thought of the stuff as magical weren’t totally wrong; period blood is made of more than regular blood. It also contains immune cells, vaginal discharge, bacteria, and endometrial tissue.
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Myth: Only women get periods.
Gender is a construct, y’all. There are plenty of trans men and non-binary folks out there who also happen to menstruate. As trans model and star of a 2016 Thinx campaign Sawyer DeVuyst says: "A human with a uterus and ovaries that work is going to get their period — it doesn’t matter if you’re a man or a woman. And there are also women who don’t get their period. And trans men, there’s a whole spectrum of trans masculinity, and some people do get it, [but] some people don’t even have that anatomy anymore — it’s complicated.”
And it’s important to acknowledge that it’s complicated, and that no two cycles are alike.
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Myth: Bad cramps are just a part of life.
As recently as 1984, psychoanalysts theorized that uncomfortable symptoms of menstruation, including cramping, were more troublesome for women who “rejected their femininity” or were otherwise “overly masculine.” The insidious suggestion there is that “real” women either don’t have cramps or that there’s something wrong with you if care enough to complain about your monthly pains. This is just another example of how periods have been politicized, rather than treated as a simple bodily process.

The truth is that, yeah, there are some uncomfortable side effects to shedding the uterine lining, such as cramping that can be debilitating in some cases. If that’s your experience, you should definitely speak up and demand that your doctor take you seriously. Extreme cramping can be a sign of problems such as endometriosis, which is when endometrial tissue grows on organs outside the uterus. Many people with endo go years before receiving a diagnosis, in part due to this myth that monthly pains are just the way it is for women. In the case of endo, hormonal treatments and surgical procedures to remove the extra tissue can help.

Even if it’s not endometriosis, though, no amount of cramping is worth dealing with if you don’t want to. Treatments such as hormonal birth control options and prescription or over-the-counter painkillers can also be helpful.
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Myth: Cramps are a symptom of PMS.
This myth isn’t as harmful as the others mentioned here, but it’s still worth a correction: PMS is what happens pre-menstruation, and it’s different from the cramps you feel once your period starts. “PMS usually lasts for about six or seven days, and it ends the day you start bleeding,” says Fahimeh Sasan, DO, assistant professor of obstetrics, gynecology and reproductive medicine at the Icahn School of Medicine at Mount Sinai.

The big distinction? PMS is caused (at least in part) by hormones rising and falling during the luteal phase, along with changes in brain chemicals that are also happening at this time. Period cramps, on the other hand, are the result of muscle spasms as the uterus sheds its lining.

It’s also totally normal to feel tired and crappy during your period, too — but technically, that’s no longer PMS. In this case, your fatigue could be due to hormones (estrogen and progesterone generally drop at the beginning of your period), but more likely causes are disturbed sleep or a heavy blood flow that could, in extreme cases, cause anemia.
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Myth: It’s bad to skip your period.
On that note, it’s totally fine to just skip the entire period process if you want. If your cycle really bugs you, whether it’s PMS or cramps, you can stop the whole dang thing by simply skipping the sugar pills in your birth control pack or using the vaginal ring.

While you might think of it as unnatural, “There is no benefit to your body cycling, compared to taking the pill or vaginal ring continuously,” Karen Meckstroth, MD, professor of obstetrics, gynecology, and reproductive sciences at San Francisco General Hospital told Refinery29 in June. “Some women think of this differently when they consider the natural process that happened before modern times, which would be pregnancy or breast-feeding throughout all of your reproductive life.” In other words, many fewer periods.
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Myth: Birth control can help PMS, but only if you skip your period.
Hormonal contraceptives are one of the most effective ways to treat bad PMS because they even out estrogen and progesterone levels throughout the month. “You don’t get that fluctuation in the luteal phase, so you don’t experience the same symptoms you would naturally,” Dr. Sasan says.

That’s generally true whether you’re on a birth control schedule that skips your period or not. “Since the actual bleeding part is not symptomatic for people, you can still have your period and not have the premenstrual symptoms.”

It’s still safe to choose a birth-control method that does take away your periods, or to skip your pills’ placebo week, for other reasons — like to eliminate cramps — Dr. Sasan points out. But that alone likely won't have much of an effect on PMS symptoms.

One thing that won’t treat PMS? Non-hormonal birth control, like condoms or diaphragms. IUDs won’t work, either, (whether they’re the hormonal type or not), since they don’t stop ovulation or the subsequent hormonal changes, Dr. Sasan says.

If you can’t or don’t want to be on birth control, talk to your doctor about other things that might relieve your PMS symptoms. A sedentary lifestyle can sometimes make PMS worse, so getting regular exercise and eating a healthier diet (full of whole foods like plenty of fruits and veggies and lean proteins) may help.
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Myth: You can’t get pregnant from period sex.
True, it’s much harder to conceive during period sex, but it’s not completely impossible, either. It can happen because most sperm can live up to five days (and some super sperm can make it seven days) inside the female body, so if you ovulate a bit early (or you tend to have a shorter cycle generally) it’s possible that sperm and egg could end up in the same place at the same time.
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Myth: You can’t get pregnant if you’re breast-feeding.
Here, again, it’s less likely, but it’s definitely possible. That said, according to the La Leche League, if your baby is less than six months old, your periods are still absent, and your lil boo is exclusively breast-feeding pretty much around the clock still, your chances of pregnancy are less than 2%. These are pretty good odds if you’re not trying to get pregnant right away and you’re okay taking your chances. But as soon as your infant gets a little older and the breast-feeding gets a little less consistent, it’s time to use contraception.
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Myth: You can get pregnant any time during the month.
Given the many, many variables (see previous myths) involved in conception, sex ed generally teaches us that it’s better to be safe than sorry and to basically assume that we are capable of becoming pregnant 24/7/365.

But the truth is that in order to get pregnant, you must have recently ovulated, which tends to happen mid-cycle or thereabouts. Even with sperm’s ability to live for a few days inside you, this means there are days during the cycle when pregnancy just isn’t going to happen. Also good to note: Let’s say you’re trying to get pregnant. Even when you time everything right, a healthy 30-year-old woman has just a 20% chance of conceiving during any given menstrual cycle.

That said, if you’re not actively TTC, it’s still a good idea to use effective birth control every time, whether that’s condoms or taking your daily pill. Your cycle can vary a bit each time, and though there are some signs of ovulation, it’s not an exact science.
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Myth: Swimming with your period leads to shark attacks.
Finally, now on to the important myths, you’re thinking. Full disclosure: We realize this is a silly one, but it really is one that people still flip out over. (Google it to see what we mean.)

While it’s true that sharks are extremely sensitive to blood in the water, there is no evidence to suggest that menstruating people are more likely to be attacked by sharks, according to experts at the Florida Museum of National History. In fact, sharks are actually attracted to many types of bodily fluids, including urine, which doesn’t stop anyone from peeing in the ocean.

Bottom line: Shark attacks are incredibly rare, and they are historically more likely to happen to those assigned male at birth (likely because cis men used to be more likely to surf; now that more women are getting into water sports, shark attacks among women have indeed risen). Still: Please feel free to swim, surf, and float regardless of your menstrual cycle.
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Myth: Periods are basically urination.
Another silly one. Well, actually, let’s just all admit that this one is straight-up batshit insane. Earlier this year, a certain teenager decided to register his disdain for people who want to repeal the tampon tax by tweeting, "Tampons should not be free. Why does everyone keep saying they should be?? If u can't control ur bladder then that's not taxpayers problem!"

He followed the first one up with this: “pay for ur own tampons if u can't hold it until you get to a toilet. I don't urinate everywhere and expect free nappies #selfcontrol."

First of all, sir, your tone is very rude. And second of all, that’s not...how periods work. In the spirit of education, here’s the official ruling on what happens: Menstrual blood comes from the uterus, via the vagina. Urine comes from the bladder, out through the urethra.
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Myth: People’s periods sync up.
Also known as the “alpha uterus myth,” this one posits that those who spend time together tend to menstruate together, and that whoever has the most powerful uterus or hormonal shifts is the alpha who determines the timing of the cycle.

While there is plenty of anecdotal evidence of this (everyone who’s lived in a sorority house knows it), the fact is there is only one 1971 study documenting the phenomenon, and other research has failed to replicate the results.
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Myth: Periods are influenced by the moon.
On a similar note, there’s also no evidence that the moon has any effect on your period. The moon has long been associated with menstruation because the lunar cycle also happens to take roughly 28 days. But scientists have been unable to document any such link.

Also: Although it has become trendy lately to attempt to sync your period with the lunar cycle, specifically with the new moon or dark moon phase, there are no true health benefits of doing so. But hey, if it helps you connect with the spirit realm, we are not ones to judge.
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Myth: You shouldn’t work out on your period.
In fact, your period may be the best time of the month to work out, depending on what you’re doing. During the bleeding phase of your cycle, estrogen and progesterone are at their lowest, allowing your muscles to access glycogen as an energy source more easily, says Stacy Sims, PhD, an environmental exercise physiologist at the University of Waikato in New Zealand, whom we spoke to back in July. During other phases of your cycle, your body tends to rely more on the breakdown of fatty acids, which are slower sources of energy, she explained. What this means is that you may be able to reach higher intensities faster during period workouts.
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Myth: A late period definitely equals pregnancy.
If you’re not trying to get pregnant, a late period is almost always a source of stress. But before you jump to that conclusion, you should know there are many reasons it could be late. These could include stress or your birth control method. The pill works by giving you a continuous dose of hormones that thins your endometrial lining. Sometimes it can thin your lining so much that even if you do choose to take the sugar pills, there’s nothing to shed during your period. Also: Emergency contraception (a.k.a. the morning after pill) may also throw things off course, so that you don’t get your period at a normal time.

A consistently late or irregular period could also be a sign of another health issue, such as a thyroid problem, extreme weight loss, or polycystic ovary syndrome.
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Myth: The menstrual cycle is supposed to last 28 days.
The 28-days thing is just an average. Thanks to the invention of period tracking apps, many of us are more in tune with the rhythm of our cycles than ever. This is A Great Thing, but because of the enduring myth that a healthy cycle lasts a perfect 28 days, those of us who come to realize ours are more like 24 to 27 days (or 31 to 33 days) may worry we’re not normal or healthy.

The truth is that anywhere between 21 to 35 days is considered normal, according to The Mayo Clinic. It’s also normal for your cycle to change drastically throughout your life. In your teens, your body is still adjusting to the whole menstruation thing before it evens out. Later on, pregnancies and breast-feeding may also throw a wrench in things, completely changing your “normal” once again.
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Myth: Your digestive issues have nothing to do with your period.
There is a reason you have to poop so much on your period, and the blame rests squarely on the shoulders of two bodily chemicals that ramp up during this special time: prostaglandins and progesterone.

The first, prostaglandins, are what cause the uterus to contract so you can shed and expel the lining. As your body ramps up production of these hormone-like chemicals, some can also affect your nearby digestive organs, making you more gassy. Meanwhile, your levels of progesterone, which is a hormone produced by your ovaries, gradually rise throughout your cycle and then drop dramatically once you start bleeding. Progesterone is known to be slightly constipating, so when the level drops, this can make you really have to go.

These two together can have the effect of turning you into a farting, pooping, bleeding machine. Life is beautiful, isn’t it?
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Myth: Organic tampons are better for you.
Not necessarily. Makers of organic tampons say that because their products are made without scary “chemicals” and only one ingredient (organic cotton) they are better for you and better for the earth. But the truth is much, much more complicated than that.

There is no data to suggest that organic tampons are truly better for your health than traditional tampons, which are often made with cotton as well as synthetic fibers. Also: Whether your tampons are organic or not, they all still end up in a landfill, so if you’re worried about the planet, the best advice is to switch to a reusable option like a menstrual cup.

What is true, though, is that tampon manufacturers are not required to disclose exactly what’s in their tampons, and we definitely need more data about how one of the most popular medical devices on earth truly affects our bodies. Until then, though, there’s no solid health reason to spend the extra dollars on organics.
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Myth: Virgins shouldn’t use tampons or menstrual cups.
Can. This. Myth. Please. Just. Die. Already.

Virginity, as a concept, is already problematic. But if you look at the definition of it in the dictionary, it can mean “an unmarried woman devoted to religion” as well as “a person who has not had sexual intercourse.” Inserting a tampon or a menstrual cup won’t change your sexual experiences, or lack thereof.

If you’ve never used a tampon or cup before, there may be some level of discomfort at first. But following the directions in the box, and staying relaxed, will help.
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Myth: Period sex is bad for your health.
Sure, it may get messy, but unless you just dislike it, there’s no reason to avoid period sex. In fact, some research suggests that orgasms may help alleviate menstrual cramps.

Note: Period sex can increase your susceptibility to certain STIs, including HIV, so be extra careful to use condoms if you are unsure about your partner’s status.
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Myth: PMS isn’t real.
It's true that, for all that PMS gets talked about, we really know very little about it from a scientific standpoint: A recent report found that five times more studies have been done on erectile dysfunction than on PMS, despite the fact that the former affects a much smaller percentage of the population. (Thanks, science.)

Maybe that’s why there’s so much mystery — and misinformation — about the topic. But here’s what scientists do know: PMS is real, and about 85% of people with periods experience at least one symptom, such as mood swings, food cravings, headaches, breast tenderness, and more, during their monthly cycle.
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Myth: PMDD isn’t real, either.
About 3-8% of people with periods are estimated to have premenstrual dysphoric disorder, or PMDD, a severe form of PMS that includes a strong emotional component. PMDD is a recognized psychiatric condition, and you must meet certain diagnostic criteria to be diagnosed. (Symptoms can include feelings of sadness or despair, panic attacks, mood swings or frequent crying, lasting irritability, and trouble sleeping.)

People with PMDD should be treated by a psychiatrist, says Dr. Sasan, and sometimes need an antidepressant to feel better and function normally. Like many psychiatric conditions, however, it’s not always seen as “real” disorder or a legitimate excuse for medication — a stigma that could make some hesitant to seek treatment.
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Myth: People with PMS have more hormones than others.
Yes, hormonal fluctuations during the luteal phase (the week or two after ovulation but before your period) are thought to play a role in many of the symptoms of PMS, from bloating to breast tenderness to emotional sensitivity. “But the difference in reproductive hormone levels [is] indistinguishable between someone who gets PMS and someone who doesn’t,” Dr. Sasan says.

The real reason PMS symptoms vary from person to person isn’t known for sure. Dr. Sasan says it has something to do with a “personal response to the change in hormones — some just react to it more than others.” And recent research suggests that levels of inflammation in the body may play a role, as well: In one study, women with higher levels of C-reactive protein (a marker of inflammation) in their blood were more likely to experience dull, painful cramping before their periods.
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Myth: Every bad mood is caused by PMS.
We shouldn’t have to explain it, but enough people say it that it’s worth spelling out: Hormonal fluctuations before a person’s period are not the only reasons they may be feeling moody.

In fact, many don’t even experience emotional symptoms related to PMS. The truth is, it’s complicated: In a 2012 literature review of previous research, only about 15% of studies found that women had “classic PMS” mood changes during the luteal phase of their cycle. Most of the studies found no association between mood and any particular time of the month, and a few actually found that women reported worse moods outside of the typical PMS window.

So does this mean PMS mood swings are a myth, or simply a product of our society? Not necessarily, says Dr. Sasan. “To me, it supports the idea that they don’t happen to everyone, but that for some women they are very real,” she says.
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Myth: Your PMS is the reason your S.O. is pissing you off so much.
If you’ve been told by a male partner that you’re no fun to be around while you’re PMSing, that could say more about him than it does about you. This theory is controversial, of course, but one Australian psychologist has suggested that men’s reactions — not women's hormones — are the real cause of premenstrual mood swings.

Citing the evidence that people who get PMS are biologically the same as those who don’t, Jane Ussher, PhD, asserts that something in a woman’s environment must be the real trigger. Her research shows that women in supportive relationships tend to report less severe PMS symptoms than those whose partners have negative connotations of PMS or those who feel overburdened with household responsibilities, suggesting a self-perpetuating cycle of emotional distress.

She’s even found that women in same-sex relationships are more likely to have supportive and understanding partners and fewer PMS symptoms overall. Sounds like it’s time for guys — at least the guys in those studies — to step up.
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Myth: You’re supposed to lose a lot of blood during your period.
It varies from person to person, but anywhere between four teaspoons up to a cup of blood is normal.

What’s not: Super heavy bleeding, which causes you to change your tampon or pad every hour for several consecutive hours. This amount of blood loss month after month can lead to health issues such as iron deficiency anemia, which causes fatigue. And it can also interfere with your sleep if you’re constantly waking up to change your protection. Like bad cramps, this isn’t something you need to just deal with. Here, again, hormonal birth control methods can make it so your periods aren’t interfering with your life.
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Myth: You shouldn’t sleep wearing a tampon.
Whether you sleep with a tampon in is up to you. The only recommendation is that you change it every four to eight hours to prevent irritation and infections, including serious ones like Toxic Shock Syndrome (TSS). (TSS is very rare these days, but your best protection remains changing your tampon regularly.)

So, sure, if you’re planning on sleeping in tomorrow, maybe think twice about leaving your tampon in until late afternoon when you finally wake up. But let’s be honest with ourselves: Most of us aren't getting more than eight hours of sleep a night regularly. So if you change it before bed, odds are you’re good to go until you wake up.
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Myth: You shouldn’t go to the dentist while you’re on your period.
There’s a myth on the internet that seeing your dentist while you’re on your period will make your teeth fall out. The idea is that hormonal fluctuations may increase “tooth mobility,” so that if you have your teeth cleaned or have any dental work done during this phase of your cycle, they may actually come loose.

Thankfully, researchers looked into the myth back in 2013, and found no evidence that your teeth become looser at any point during your menstrual cycle. Interestingly though, they did find that during ovulation and the two weeks before the women’s periods started, the women’s gums tended to be more irritated. This suggests that it may in fact be better to get your teeth cleaned during your period or right after, when your gums may be less sensitive to poking and prodding.
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Myth: Blood always equals a period.
Your period is far from the only source of vaginal bleeding. Some women (but not all) experience regular mid-cycle spotting when they ovulate. There is also something known as “implantation bleeding,” which is a very early sign of pregnancy and is caused by the fertilized egg burrowing into your uterine wall.

Also: Don’t freak out if you see some brown or even black stuff in your underwear, especially toward the end of your period. Brown or brownish-red discharge can happen at the end of your period as older flow is being flushed out. Ovulation bleeding may also be brown or brown-ish red.

All this said, vaginal bleeding can also be a sign of infection, a benign uterine tumor (a.k.a. a fibroid) or polyp, miscarriage, a side effect of the IUD, and more. So, if you’re experiencing any weird or abnormal bleeding, definitely check in with your doctor. It could be a fluke or normal ovulation bleeding, but you definitely want to know if something is up.
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