Lunar effect purported lunar-lunacy connection, and at least 20 published studies on the purported lunar-birthrate connection. This has allowed several extensive literature reviews and meta-analyses to be produced, which have found no correlation between the lunar cycle and human biology or behavior. Examples of the belief have been found in ancient Assyrian/Babylonian writing. Claims of a lunar connection have appeared in the following contexts: It is widely believed that the Moon has a relationship with fertility due to the corresponding human menstrual cycle, which averages 28 days. However, no connection between lunar rhythms and menstrual onset has been conclusively shown to exist,
Menstrual synchrony there was no evidence the women in this study synchronized their menstrual cycles. Ziomkiewicz conducted a study with 99 Polish college women living in two dormitories. Thirty six of the women lived in 18 double rooms and sixty three lived in 21 triple rooms. Women recorded their menstrual cycle onsets on menstrual calendars provided to them and 181 days' worth of menstrual cycle data were collected. The mean menstrual cycle length was 30.5 days (SD = 4.56). Based on the mean cycle length of the women in this study, the expected difference by chance in menstrual cycle onset was approximately