Recent research has sparked new discussions surrounding the connections between menstrual cycles and natural environmental factors, such as light exposure and lunar phases. Emmallee Ford, a reproductive health researcher and the study’s first author on the work published in the journal Science Advances, conducted among a large, nationally representative cohort based on women’s retrospectively self-reported calendars of menstrual cycle dates. These findings cast doubt on the assumption that historic claims of connections between menstrual and lunar cycles had any grounding in reality. With new tracking methods, these links have been all but eliminated.
Dr. Ford emphasized the importance of acquiring natural light throughout the day. He illuminated how important it is to embrace darkness at night for the health of our menstrual cycles. She explained that high levels of artificial light at night could throw off this balance, causing irregularities. The study missed several lunar cycles, including full moons and eclipses, and it could not compare these natural phenomena against known menstrual records. They found that the synchrony of these cycles has been declining in occurrence through time.
The study raises serious questions about the validity of much previous research. It challenges the popular belief that there is a strong link between menstrual cycles and the lunar cycle. Dr. Ford raised the issue of how previous research has been often undergirded by weak data. More importantly, they overlooked the development of new, sensitive and secure period-tracking technology.
The Importance of Natural Light
Dr. Ford went on to stress just how important exposure to natural light is on our biological rhythms, cycled nature of which regulates even our menstrual cycles. She pointed out that exposure to natural daylight throughout the day can affect hormonal balance in women to increase mood and well-being. She cautioned that artificial light at night can disrupt circadian rhythms.
“Essentially, you go from having nice rhythms where your body knows when it’s day or night to low amplitude rhythms where your body’s a little more confused,” – Sean Cain, researcher at Flinders University.
Research indicates that the disruption of circadian rhythms can lead to a variety of health issues, including irregular menstrual cycles. Dr. Pecoraro, an obstetrician and gynecologist, emphasized the connection between artificial light exposure and reproductive health. He thinks this type of connection deserves far more research.
“There is some data that light does affect functioning of the brain, and the brain does affect everything in the body,” – Dr. Pecoraro.
The interactions between natural light, the synthetic world, and the endocrine system are possibly deeper than we ever knew. As more women turn to period-tracking apps, it becomes essential to consider how lifestyle factors like light exposure influence menstrual health.
Reevaluating Lunar Cycle Connections
Throughout history, countless scientists have tried to establish links between menstrual cycles and lunar cycles. She mentioned research from the 1980s and earlier that indicated a connection between the two occurrences. Now, over a decade later, with improvements in accessibility and analytics methods, those relationships seem to have dissipated.
“We’ve continued to find out more about the interplay between the natural environment and how our bodies work,” – Dr. Pecoraro.
The interdisciplinary research team applied self-collected menstrual charting data to scientific lunar phase definitions, using robust data from prior to 2010. They found several statistically significant relationships indicating that periods are indeed synced to the moon. As tracking methods improved, those correlations started to wane.
Astrophysicist Jonti Horner was less than impressed with this connection between menstrual and lunar cycles. He added that from an astronomical perspective, it would be pretty hard to justify any major correlation.
“The idea of a link between menstrual cycles and lunar cycles really doesn’t make sense,” – Jonti Horner.
Experts warn against drawing sweeping conclusions from past research as the study indicates waning connections with current data.
The Limitations of Current Research
Though the discoveries in Ford’s study are a positive step towards advancing knowledge on menstrual health, experts stress there’s not enough women included. In her presentation, Dr. Pecoraro noted that the research was limited due to small sample sizes and self-reported data.
“The study is hampered by small numbers and difficulties in objective measurements,” – Dr. Pecoraro.
Ford said recent breakthroughs with tracking technology have transformed research. Today, researchers have a treasure trove of data that helps to dispel long-held misconceptions about menstrual cycles. She warned, don’t overinterpret any of these associations.
“You’re more likely to notice when something does happen as opposed to every single time it doesn’t happen,” – Dr. Ford.
As one example, the complexities surrounding menstrual health mean we need more research into how things like climate, noise, and light pollution impact cycles. Ultimately, Dr. Ford found that many of these observations could appear meaningful upon initial inspection. They might be this happenstance rather than having any sort of pattern develop.
“We cannot rule out the possibility that our observations are coincidences. However, I think this is highly unlikely,” – Professor Helfrich-Förster.
