For the duration of human existence, the menstrual cycle has been a source of myth, superstition and debate. We’ve started to move away from thinking that burning a toad will help with a heavy flow, that period blood can be used as a love-charm and that sanitary products are a luxury item (the government are still a little behind on this one), but there's still one period mystery that has racked the minds of many.
Do our periods really sync up?
For the unaware, ‘menstrual synchrony’ is the idea that if you spend a lot of time with someone else who menstruates, your cycles become more synchronised. The phenomenon is sometimes referred to as the McClintock Effect after the woman who founded the idea in 1971. Using a case study of seven female lifeguards, McClintock found that after living together for three months, the onset of their cycles fell within the same 4-day period.
Unlike some of the older period myths, menstrual synchrony has at least a smidge of scientific reasoning behind it. The idea is that when you come into physical contact with someone, your pheromones interact, leading to your periods synching up.
“But is it real?” Well, that totally depends on who you ask. There is currently no medical literature that proves menstrual synchrony, and since the turn of the century, there have been a few major blows to McClintock’s theory. A 2006 study completed in China found that any signs of period syncing was merely mathematical coincidence. In 2017, Oxford University and everyone’s favourite period-tracking app Clue conducted a large study that, as a true scientist would say, wiped the floor with McClintock’s research papers.
These findings should effectively push period syncing into obscurity with the burnt toads and the bloody love potions. But, and it’s a big but, many of us ovary-owners find the phenomenon so common that we regard it as a fact. William James, a man who was both a philosopher and a psychologist, coined the term “the will to believe” to describe the adoption of a belief without any evidence. If belief in horoscopes and karma has taught us anything, it’s that people want to find significance in the events of their lives, even when they are nothing more than happenstance.
While the “right” answer can be found in science, it’s also part of our nature to believe in the most wonderous, exciting options. Menstrual synchrony could be nothing more than a silly fairytale in the eyes of some, but for others, it allows them to believe in the power of their bodies and of their connections to the people around them.
So can menstrual synchrony be regarded as scientific fact? Absolutely not. Is belief in the theory hurting anyone? Nah, not really. If you ask me, if you’re going to be curled up in a ball crying, you might as well believe there’s something magical about it.