Is Menstrual Synchrony Real?

April 9, 2015

In the early 1970s, a young graduate student called Martha McClintock started to notice something strange happening in her dormitory. All the women’s cycles slowly started to match up. In fact, by the end of the semester, almost all the women’s cycles were within a 4-day period.

Since this initial discovery, the existence of menstrual synchronies has been controversial in the scientific world. Many women claim to have experienced this phenomenon first hand, however current scientific data does not support this idea. Whether or not this theory is true, there are some interesting theories as to what causes menstrual synchrony.

What is Menstrual Synchrony? | How Does Menstrual Synchrony Work?

No one really knows why menstrual synchrony happens. There have been several hypotheses as to why women living in close quarters may “synch up.” Scientists believe that women may release pheromones that could cause menstrual synchrony. The theory is that some women release stronger pheromones that change the cycles of other women.

Other scientist have hypothesized that menstrual synchrony might have something to do with women synching up with the lunar phases. Many women today still claim that their cycles are controlled by the phases of the moon.

While it may be interesting to ponder what could be affecting a women’s cycle, there is currently no scientific evidence to support the idea that pheromones or the moon affect women’s periods.

Is Menstrual Synchrony a Myth?

The validity of menstrual synchrony is still much debated in the scientific community. While McClintock’s research was at one point widely accepted, many modern day scientists call into question her methods. They believe that she did not have a large enough study sample, nor did she track her subjects long enough. Additionally, many other scientists have tried to repeat McClintock’s experiment and failed to find any evidence of menstrual synchrony.

Today, menstrual synchrony still lays somewhere between fact and fiction, with many women claim to have experienced the phenomenon first hand. However, there is little scientific evidence to back up those statements.

One explanation as to why women’s cycles start to overlap is a simple probability. A woman’s menstrual cycle can range anywhere from 28 to 35 days. Over time, women on different frequencies will line up. This happens purely by chance, and has nothing to do with pheromones or lunar phases.

What Do You Think?

Despite what current research says, many women have claimed to experienced menstrual synchrony with their roommates, sisters, close friends and even coworkers. So what do you think? Have you ever experienced menstrual synchrony? Let us know what you think by leaving a comment on our Facebook page.

If you have any other questions about changes in your period, feel free to call OB-GYN Women’s Centre today! Our caring physicians are there to answer any and all of your period questions. Just give us a call, or schedule your appointment online.