Light pollution and synchronization with lunar cycles
25.09.2025
The University of Padua participated in an international study demonstrating how light pollution is compromising the synchronization between women's menstrual cycles and the lunar cycle. Many animal species regulate their reproductive behavior according to specific lunar phases to improve their chances of successful procreation. Although the influence of the moon on human reproductive behavior is still a subject of debate, the female cycle has a duration very close to that of the lunar cycle.
It has been observed that women's menstrual cycles intermittently synchronize with lunar luminance cycles (the amount of visible moonlight throughout the month, varying from New Moon to Full Moon) and with the gravitational influences of the moon (which cause tides). However, with age and increasing exposure to artificial nocturnal light, this synchronization tends to diminish.
A study published in the journal "Science Advances", with contributions from Sara Montagnese, Alberto Ferlin, and Rodolfo Costa of the University of Padua, analyzed data from 176 women who had recorded the start of their cycle for at least two years, noting that until 2010, they were clearly synchronized with the lunar cycle. After the massive introduction of LED lighting and the widespread use of smartphones, this synchronization became evident only in January, when the gravitational forces of the Sun-Earth-Moon system are strongest.
Using Google Trends, which highlights interest over time for specific topics, the researchers confirmed that the increase in light pollution has interfered with the synchronization of menstrual cycles with lunar luminance cycles.
"It thus seems likely that the growing nocturnal exposure to artificial light interferes with the synchronization with lunar luminance cycles," explains Sara Montagnese. "Overall, the synchronization between the female menstrual cycle and lunar cycles is therefore reduced compared to the past and remains detectable mainly during periods when the gravitational forces in the Sun-Earth-Moon system are more intense."
These results could have significant implications for physiology, behavior, and fertility, especially considering the reduction in fertility in the Western world.
