Period Syncing? Myth or Fact?

"You're on your period too? No way, me too!"

We've all said that to our close friends, roommates, or colleagues at some point in our lives. Do our cycles actually sync with other menstruators around us? Can it be scientifically proven, or is it too mystical to be true?
Let's find out! 

The McClintock Effect  

Named after Martha McClintock, McClintock (1974) believes that women’s pheromones communicate with each other due to physical closeness, triggering cycle syncing. Pheromones is a secreted chemical factor that triggers a social response in members of the same species, it is capable of acting like hormones outside the body of the secreting individual, to impact the behaviour of the receiving individuals.

According to McClintock’s study, an alpha uterus has a “strong hormonal pull that causes other cycles around it to menstruate in unison.” 

 

Mathematical Coincidence?

Researchers noted that any group synchrony that occurred was “at the level of chance,” and variability of period cycles over time inevitably resulted in “convergences and subsequent divergences of cycle onsets.”  

This could make someone assume they're syncing with other people's periods when it’s actually just a coincidence when cycles line up. (Yang and Schank, 2006) 

Before attributing your syncing to a close friend, know that your usual cycle can be interrupted by hormonal birth control, stress, medications, health conditions, and disordered eating. Period Syncing needs more research to be done on, it’s been unfortunately overlooked like other women’s health topics generally.