Karen Fratti
March 24, 2017 12:54 pm

You’ve likely heard this myth and might have even experienced it yourself: your period syncs up with other women’s periods who are close to you. It’s a very common thing that seems to happen all the time, whether it’s your BFF, your mom, your co-worker, or your roommate. Well, we have some news for you that might be shocking at first. It’s all in your head — and there’s data to prove it.

HelloGiggles chatted with Clue, an app that allows you to track your period, your PMS, and even your fertile window. Their researchers reached out to Clue users to dig into whether their periods synced up with women around them. Out of 1,500 survey responders, there were only 360 pairs over a course of three random menstrual cycles. The researchers then looked at three consecutive menstrual cycles for those pairs and over time, 273 of those pairs actually started to diverge from each other.

In fact, most of the women who thought they were syncing with a roommate were actually getting their periods at different times.

So what gives? A lot of times it actually does seem like you’re syncing up with your besties, right? Clue’s data scientist Marija Vlajic tells HelloGiggles it’s partly because our brains are wired that way.

That makes *complete* sense right? If your friend tells you she has her period, aren’t you immediately like, “Ugh, me too.” And if you don’t have yours, you’re more likely to just brush it aside and give her the squad’s permission to just stay in and watch Grey’s Anatomy all weekend.

So what about all the times you’ve actually synced up with all your friends on vacation? It’s just math, ladies. This summer Simon Oxenham wrote in New Scientist that if you crunch the numbers, you’ll see why we tend to think we’re syncing up with people. There are only 28 days in a cycle, and periods can last anywhere from a few days to a whole week. If you have a group of five friends, there are only so many times you could all be menstruating. At some point, the days are going to match up.

In addition to that, Vlajic tells HelloGiggles that society has always believed that women sync up with each other. “For centuries, many people have observed that their cycles match up with friends or family members with whom they spend most of their time — especially if they live together,” she says,

This whole myth was hammered into popular culture in 1971 when Harvard University researcher Martha McClintock published the first study saying that women synced up in Nature magazine. She found that some women synced up and spread the rumor that this was a real phenomenon.

But there’s a catch!

McClintock’s study has since been totally debunked by the science community that her methodology was off, yet the rumor still persisted. Mainly because, as we know all too well, back in the 1970s there wasn’t a lot of research being done about women’s reproductive health.

Yea, tell us about it. Vlajic also believes that women, or just humans in general, “are naturally inclined to want to believe in the notion of cycle syncing as it makes us feel more connected with those close to us.” For sure, it can make you feel more connected to your fellow females, but the idea that our menstrual cycles are controlled by the moon also makes it sound like women are merely at the mercy of nature, rather than fully functioning, totally autonomous human beings.

We know we’re goddesses, but our periods aren’t *magic.* They’re part of our biology.

Sure, it’s biology we should be proud of and learn about, but it’s biology at the end of the day. Our periods are totally natural, but we’d be silly to think they’re irrational or mystic. Perpetuating the myth that our bodies and periods magically sync up with whoever we’re hanging out with can actually hold women back, since it makes it seem like our periods control us and make us do strange things. In a way, this is similar to men insisting that women can’t be premenstrual and be effective leaders at the same time. Which is obviously complete rubbish.

While the myth of syncing sounds interesting, it’s really nothing more than a misunderstanding of how our bodies work — and it could lead to further stigmatization of periods if we’re not careful. Which is why we need more studies done about our periods. Because the more we learn about our bodies, the better.