Once a month, I send a text to my group chat announcing that I’m on my period. I do this for a few reasons. Firstly, I want to give my friends a heads up that I might not be feeling my best and could bring some negative energy to our conversations. Secondly, I’m secretly hoping that one of my friends will offer to buy me Starbucks or do something nice for me. And thirdly, it’s possible that some of my friends might also be on their periods, and I want to create a sense of camaraderie.
When I send my announcement, I usually get responses from my friends saying that they’re also on their periods. It’s comforting to know that we’re all going through the same thing and can support each other. It’s a relief to feel like we’re in it together.
I used to think that period syncing was a proven scientific fact, and I’m not alone in this belief. In fact, 70% of people who menstruate have experienced period syncing. However, it turns out that there’s not a lot of scientific evidence to support the idea. Nonetheless, it’s a shared experience that many of us can relate to.
Although period syncing has been a topic of discussion among friends for a long time, it was not until social psychologist Martha McClintok investigated the phenomenon in 1971 that the scientific community began to take an interest in it. McClintok studied 135 women living in the same dorm and had them track their periods throughout the school year. She found that their menstrual cycles tended to sync over time, theorizing that it occurs through sharing pheromones.
Pheromones are chemical signals secreted by animals, insects, and some plants that can be detected by their same species. In humans, they are believed to play a role in attraction, among other things. According to one theory, pheromones make periods sync as an adaptive mechanism that has evolved over time. If our cycles are the same, there is a higher possibility of getting pregnant at the same time, leading to benefits such as increased social support, shared childcare responsibilities in the community, and a population boost.
However, since McClintok published her findings, scientists have conducted several studies on roommates, couples, animals, and friends, with mixed and often conflicting results. Many of these studies fail to show any kind of syncing at all, including a Chinese study from 2006 that collected period data from 186 students living together in a dorm and research published by Oxford in 2017 that showed periods were more likely to step out of sync.
To make matters even more complicated, there is still no concrete evidence that humans even have pheromones in the first place. While it is likely that human sex pheromones exist because we are animals, the scientific community remains divided on this issue. At present, there is no proof that we secrete chemicals that alter the behavior of other people. So, what is the explanation for what 70% of people experience, and what was McClintok talking about in 1971?
So, after all these years, it seems that the magical and mysterious phenomenon of period-syncing might just be down to… probability and chance. As someone who struggles with math, I can’t believe that this beautiful thing that brings us together and fosters empathy among menstruators can be explained by something as simple as probability.
In essence, due to the varying lengths of menstrual cycles and periods, it is highly likely that at some point, you and your friends will align. It’s simply a matter of chance and how it coincides on the calendar.
While it may be disheartening to learn that this phenomenon may just boil down to statistics, it’s important to remember that the research surrounding women’s health is still evolving. Conducting accurate studies can be challenging due to the multitude of factors at play. As we continue to learn more about our bodies, we may gain a better understanding of period-syncing.
Although the explanation may seem mundane, it doesn’t have to detract from the special bond that comes from sharing this experience with others. The sense of community that arises from commiserating with friends can still be a meaningful part of the menstrual journey.
In the end, any opportunity for connection is something to be cherished.