Do lunar phases influence menstruation? A year-long retrospective study.

Area of Science:

• Gynecology and Reproductive Health
• Chronobiology
• Lunar and Astronomical Influences

Background:

• Traditional beliefs and anecdotal evidence suggest a connection between lunar cycles and menstruation.
• Previous short-term studies have offered conflicting or inconclusive findings on this topic.
• Understanding potential environmental influences on reproductive cycles is crucial for women's health.

Purpose of the Study:

• To investigate the potential synchrony between the onset of menstruation and lunar phases.
• To provide robust, long-term data to address the persistent belief in a menstrual-lunar cycle connection.
• To analyze a large dataset of menstrual cycles and lunar phases using advanced statistical methods.

Main Methods:

• Cross-approximate entropy analysis was employed to assess potential synchrony.
• Data included 980 menstrual cycles from 74 women over a full calendar year.
• Menstruation onset dates were compared against corresponding lunar phases (new moon, full moon, etc.).

Main Results:

• No statistically significant synchrony was detected between menstrual cycle onset and lunar phases.
• The findings were consistent across the entire year-long study period.
• Results contradict some previous short-term research and popular beliefs.

Conclusions:

• This long-term study provides strong evidence against a direct link between lunar phases and the menstrual cycle.
• The findings suggest that perceived correlations are likely coincidental rather than causal.
• Further research may explore other environmental or biological factors influencing menstrual cyclicity.