Put any number of women in a room, wait for one to announce that she's on her period, and—without fail—another woman will excitedly say, "Wait, me too!" Because of references in pop culture (like that scene in Sex and the City where Carrie and the gals realize they're all menstruating at the same time!) and some bullshit myth everyone heard in middle school about female hormones being spread from person to person with every touch, "period syncing" has long been believed as something that really happens. Any group of menstruating individuals will eventually start bleeding at the same time every month if they spend enough time together. Their periods sync. It's both creepy and a sign of ~sisterhood~, almost coven-like, which is probably why people are so into it.
But, as always, science has come to spoil all the fun. According to a new study carried out by the fertility app Clue and the University of Oxford, period syncing isn't a thing. As reported by the Guardian, this particular period syncing study is the largest of its kind—researchers pared the survey sample down to 360 pairs of women who were living together and analyzed three consecutive menstrual cycles for each pair. They found that a vast majority—273 pairs of the 360—had a greater difference in the period start date by month three than they had in month one, leading scientists to believe that period syncing is more coincidence than it is a sign of bloody feminine bonding.
"It’s very unlikely that cycle syncing is a real phenomenon," Marija Vlajic, Clue's data scientist, told the Guardian. "We’ve also done some statistical tests and found that the difference in cycles actually grows. This doesn’t mean that pairs go out of sync—it means they were never in sync in the first place."
Think of it this way: Every single menstruating person on this planet has a different cycle length. Your own cycle length has probably changed several times throughout your lifetime or maybe even changes several times in a year. What this means is that, at some point in the course of your relationships with other women, your periods are bound to align from time to time, just because there are only so many days in the month. And then your periods are also bound to slide back out of congruency. There's no ~mystical power~ or witchy thing going on here—it's just pure coincidence.
Still, this doesn't take away from the fact that it can be sorta fun to realize you and a friend are both going through the same level of misery at the same time. Just as you've probably felt left out when all your friends realize they're on their periods at the same time, you've probably felt a small spot of joy when you're "synced up" with a close friend. This is because commiseration is powerful, periods are shitty, and it's nice to know someone is dealing with the same tough things as you are. Enjoy the rare months when you and all your closest pals are going through four tampons a day. And if you wanna believe that it's a sign that you're all closer than ever and are blood sisters, well, that's your call.
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This article originally appeared on Cosmopolitan.com. Minor edits have been made by the Cosmo.ph editors.