The artificial light of LEDs and mobile phones led to a disruption in the last decade of menstrual cycles alignment with the moon.
For centuries, folklore has connected women’s menstrual cycles to the moon phases. Now a new published in Science Advances suggests that the connection was real – but disappeared largely in the last decadecoinciding with the widespread use of smartphones and LED lighting.
A team from the Julius-Maximilians University of Würzburg examined records of 176 women covering almost 100 years. The data combined manuscript records from the mid -twentieth century with entries in the 2000s. Before 2010, menstrual cycles usually started with full or new moons, closely following the lunar calendar. Investigators say the alignment was too consistent and widespread to be discarded as mere chance.
But after 2010, the pattern disappeared dramatically. The only exception was January, when the combined gravitational attraction of the sun and the moon Reaches the peak every yearstrong enough to nullify artificial light. This discovery points to a double influence: cycles respond not only to moonlight but also to lunar gravity.
The study found that women’s cycles corresponded to three lunar rhythms: The phase cycle of 29.5 days and two shorter gravitational cycles of about 27 days. This synchronization may have guided the reproductive rhythm.
However, the Increased light pollution seems to have drown out the sign of nature. The brightness of the LEDs and screen of the smartphones emits blue light that interrupts the circadian rhythms and obscures the moonlight. Satellite images have confirmed a sharp increase in night brightness since 2010, especially in urban areas. Online search trends also show peaks in January at consultations on menstrual cramps, echoing the gravitational effect, refers to.
The duration of the cycle was also important. Women with natural cycles between 26 and 36 days were more likely to align with the lunar phases. As the cycles shortened with age Or with lifestyle factors, synchronization has become rarer. The use of screens at night, which can change the duration of the cycle, can further reduce alignment.
Although the bond between the body and the sky has not completely disappeared, it became more difficult to detect it in today’s illuminated world.
“The biological clock is still working,” observe the authors, “but is often drowned out of the brightness we have created ourselves.”
