How Does the Moon Affect Your Cycle? Here’s What Science Has to Say

Welcome to POPSUGAR Uninhibited, a space where anyone with a period can come for advice, recommendations and support. Here, we’ll tackle topics like PMS, sustainability, post-partum periods and bring you first-person experiences in our period diaries. We also want to raise awareness around period poverty, with the aim to ignite change with the help of our launch partner Modibodi and charity partner Share the Dignity. You can find all of the stories here. 

The link between the menstrual cycle and the moon has long been talked about, with many scientific studies looking at this connection. It makes sense, considering the pull the moon has over the tides and the fact that both the lunar cycle and the menstrual cycle often last the same number of days.

While the phases of the moon are said to affect things like our periods, mood, sleep and energy levels, research hasn’t really been able to substantiate this. So, we decided to have a look into whether or not the moon plays a role in your period and get to the truth of the matter once and for all. Here’s what you need to know.

The Science Behind the Menstrual-Lunar Link

There are a plethora of studies relating to the lunar and menstrual cycle connection, with some prominent ones dating back to 1977. This study from the ’70s found that those who began their next menstrual cycle on the new moon had a greater chance of becoming pregnant.

More recent studies haven’t found such a link, with research from 2013, which looked at the cycle of 74 people over a period of 12 months, finding “no evidence of synchrony”. But, this might have more to do with modern life rather than a lack of connection between your periods and the moon.

According to Healthline, a study from 2021 suggests that the menstrual cycle might have once been synchronised with the moon but factors like artificial light and modern lifestyles may have disrupted this relationship.

While this was a small study, with only eight participants, it looked at period tracking data from a period of 19 to 32 years. From this, researchers found that five of the peoples’ periods synced with the lunar cycle intermittently, while three of the participants experienced period-moon synchronisation most frequently with the occurrence of a full or new moon.

The largest piece of analysis on the topic to date comes care of Clue, the period tracking app. The data science team at Clue tracked the cycles of 7.5 million people and no link between lunar phases and the menstrual cycle or period start date was discovered.

“What you normally hear is that you ovulate around the full moon and get your period around the new moon,” said Dr Marija Vlajic Wheeler, a data scientist at Clue. “Looking at the data, we saw that period start dates fall randomly throughout the month, regardless of the lunar phase.”

The team at Clue agrees that it is interesting that the length of the lunar cycle and the average menstruation cycle are pretty much the same, coming in at 29.5 days and 29 days respectively but it’s also possible that these two cycles aren’t at all related.

In saying that, there are a number of reasons people propose why these cycles are connected. According to Clue, one common suggestion is the moonlight, especially in the absence of artificial light, could have an impact on people’s biological processes.

This isn’t out of the question, considering the effect a lack of light can do, with research finding that people who work night shifts are more likely to experience irregular menstrual cycles, which is suggested as a result of light exposure.

The Cultural Connection

While the science behind the lack of a concrete link between the lunar and menstrual cycle is pretty extensive, it’s unsurprising that people still look for the connection considering how culturally significant the moon is.

There are different theories as to why this is, including the fact the two are linked in many cultures and mythologies. According to Clue, “the terms ‘menstruation’ and ‘menses’ even come from Latin and Greek words meaning month (mensis) and moon (mene)”.

While the data might not support this in a tangible way, researchers at Clue found that many people still found personal meaning in tracking the lunar cycle in relation to their periods. While we might not even have an answer as to why these cycles are so linked in society, we can appreciate the wonder of both the menstrual cycle and the lunar phases.

Always seek the guidance of your doctor or other qualified healthcare professional with any questions you may have regarding your health or a medical condition.