The idea that women living together will eventually have their periods at the same time is a popular one. Often referred to as “period syncing” or “menstrual synchrony,” this phenomenon has been a topic of conversation and speculation for decades. But is there any scientific truth behind it, or is it just a coincidence? Let’s delve into the research and explore the reasons behind why periods might seem to sync.
The Origins of the Period Syncing Myth
The concept of menstrual synchrony gained traction in 1971 with a study by Martha McClintock. Her research, conducted on a group of women living in a college dormitory, suggested that their menstrual cycles converged over time. McClintock attributed this to pheromones, chemical signals that supposedly influenced the hormonal rhythms of women in close proximity. This became known as the “McClintock Effect.”
Debunking the Myth: Probability and Statistics
While the idea of period syncing is intriguing, subsequent research has largely debunked the McClintock Effect. Statistically, given the average length of a menstrual cycle (around 28 days) and the natural variation in cycle lengths, it’s highly probable that two or more women living together will eventually have overlapping periods.
Let’s break it down: If one woman’s cycle is 28 days and another’s is 30 days, their periods will naturally align at some point. This is simply a matter of mathematical probability, not a biological phenomenon.
Tracking periods can help understand syncing patterns.
Several studies, including one conducted in China with 186 college students and another at Oxford University with over 1,500 participants, reinforced the probability argument. While periods did sometimes synchronize, researchers found no evidence of one woman’s cycle influencing another. The apparent syncing was attributed to random chance and the natural overlap of menstrual cycles.
Migraines: A Potential Link?
Interestingly, while period syncing itself may be a myth, research has hinted at a possible connection between shared living spaces and the experience of migraines in menstruating individuals. A 2017 study indicated a higher frequency of migraines among women living together. However, this study was small, and more research is needed to understand the potential relationship and rule out other factors like stress or shared environmental triggers.
Period Syncing: Myth or Mathematical Coincidence?
The overwhelming scientific consensus is that period syncing, in the sense of one woman’s cycle directly influencing another’s, is a myth. The apparent synchronization of periods is more likely explained by the probability of overlapping cycles due to natural variations in cycle length.
While pheromones play a role in other aspects of human biology, there’s no conclusive evidence to support their involvement in menstrual cycle synchronization.
Embracing the Shared Experience
Even though period syncing may not be a biological reality, the shared experience of menstruation can still foster a sense of connection and support among women. Sharing period tracking apps, planning self-care routines, and openly discussing menstrual health can create a sense of community and normalize a natural bodily function.
References
- Ferreira KS;Guilherme G;Faria VR;Borges LM;Uchiyama AA; (n.d.). Women living together have a higher frequency of menstrual migraine. Headache. https://pubmed.ncbi.nlm.nih.gov/27861827/
- MAPSS. (n.d.). https://mapss.uchicago.edu/directory/martha-mcclintock
- Strassmann, B. I. (1999, March 1). Academic.oup.com. https://academic.oup.com/humrep/article/14/3/579/632869
- Watson, K. (2019, January 23). Is period syncing a real thing? why women’s periods may sync up. Healthline. https://www.healthline.com/health/womens-health/period-syncing#obstacles-to-proving
