Are our periods really affected by the moon?

These days, we use apps and calendars to track our periods, but have you ever wondered if our cycles are actually linked to something a little bit more… cosmic? 

There are certainly many people that believe our periods sync with the moon, since the folks at menstruation app Clue have revealed that they get regular requests to add lunar cycles to its features. As for if there’s any truth in it, there’s been a number of studies looking at the moon and menstruation – and though there are some similarities between both cycles, most scientists believe that it’s merely coincidental.

In fact, tracking app Clue did an extensive study looking at moon phases and periods, analysing over 7.5 million menstruation cycles using its data. It concluded that “the menstrual cycle does not sync with the lunar cycle”, adding: “lunar and menstrual cycles will correlate more or less for some people – depending how closely their average cycle length matches the lunar cycle.”

Since the average menstrual cycle comes in at 29 days and the moon cycle lasts 29.5 days, it makes sense that many will find that they start their period around the time of the new or full moon. That said, normal menstrual cycles can last from 24 to 38 days, so it would really depend on your cycle length.

While there have been other studies looking at the relationship between the moon and periods, none were as extensive, and all had varying results.

Of course, the connection between the moon and menstruation is believed to be a powerful one in many cultures. The word ‘menstruation’ even comes from the latin word ‘menses’, or ‘month’, which in turn comes from the Greek word ‘mene’, meaning ‘moon’ – and it’s thought that Ancient Greeks believed menstruation to be a cosmic event.

These days, many still believe in the spiritual side of periods, too. We spoke to Dr Giuseppe Aragona, GP and online doctor for Prescription Doctor, about whether we really need to focus on separating fact and fiction.

“People like to link the lunar cycles to the menstrual cycle, because they are similar in their patterns and of course both the moon and the female body could be perceived as mystical and marvellous,” he says.

“Many philosophers, anthropologists and other experts have noted over the centuries that there are parallels between the two, suggesting that they might be connected, however there is little concrete evidence to prove this. Though the cycles are somewhat similar in their days, it is highly unlikely that they are linked or that they have an effect on each other. Many studies over the years have been conducted, however there is still plenty of uncertainty around it and much more work needs to be done to confirm if there are biological mechanisms at play.”

While there is no concrete evidence to suggest that the moon is linked to menstruation, there is nothing wrong with embracing the connection if you feel it, according to Dr Aragona.