Do women’s periods really sync up when spending time together?



We’ve all heard it. And maybe even swear we’ve experienced it! Have you ever spent a lot of time around a girlfriend or two and found that you seem to be on your periods at the same time?

Well, the latest rumor is that menstrual cycles do not actually sync up between women who spend a lot of time together.  And this was new research that is supporting such. 

Despite popular belief, there are currently no scientific studies that have been able to prove the theory that those with a uterus can experience synced menses cycles.


However, it has more so been disproved by a recent study performed by the period tracking app Clue and Oxford University.  This study actually debunks the myth that periods can sync up simultaneously between women that spend time together.

Clue sent app users a poll asking about their experiences of synced periods with fellow app users. The review included questions that assessed everything from  relationships to proximity and frequency of visiting friends, the use of contraceptives and more.

Out of 1,500 responses, there were 360 pairs of users who had at least three cycles over the same time period that could be reviewed.

Researchers analyzed a minimum of three cycles per pair, revealing that 273 of the pairs actually had larger gaps between the start and end dates of their cycles at the end of the study compared to its beginning. This showed that the brief amount of time that periods were in sync was just that – a brief sequence.

Of those 360 pairs, only 79 had cycles that featured start dates getting closer together. At the end of the study, results showed that periods did not sync.

The study also showed that living together did not increase the likelihood of periods syncing.


Surprisingly, not only did the study find that periods will not sync over time between those who spend a lot of time together and those who live together, it actually revealed that they are more likely to become more separate.


Which leaves the question… why does it seem as though our girlfriends are on their period every time we are? Chances are that although periods are a private matter (meaning private area), they aren’t taboo topics or private for discussion.  Hence, we talk about when we are on ours and become more aware of other women sharing their cycles as well.


It is a unique gift that sets us “apart from the boys”, so it may seem as though it is a rare occurrence that can be celebrated whenever found to be in conjunction with a fellow female friend or colleague.


What do you say?  Is science wrong?  Think that you and your friends are an exception to this study? Do tell!  

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