Idea that the menstural cycle synchronizes with those of other women in close proximity
Menstrual synchrony, also called the McClintock effect,[1] or the Wellesley effect,[2] is a contested process whereby women who begin living together in close proximity would experience their menstrual cycle onsets (the onset of menstruation or menses) becoming more synchronized together in time than when previously living apart. "For example, the distribution of onsets of seven female lifeguards was scattered at the beginning of the summer, but after 3 months spent together, the onset of all seven cycles fell within a 4-day period."[3]
Martha McClintock's 1971 paper, published in Nature, says that menstrual cycle synchronization happens when the menstrual cycle onsets of two or more women become closer together in time than they were several months earlier.[3]
After the initial studies, several papers were published reporting methodological flaws in studies reporting menstrual synchrony, including McClintock's study. In addition, other studies were published that failed to find synchrony. The proposed mechanisms have also received scientific criticism. Reviews in 2006 and 2013 concluded that menstrual synchrony likely does not exist.[4][5][6][7]
^Sapolsky, Robert M. (2017). Behave : the biology of humans at our best and worst. New York, New York. p. 11. ISBN9780735222786.{{cite book}}: CS1 maint: location missing publisher (link)
^Harris, Amy L.; Vitzthum, Virginia J. (2013). "Darwin's Legacy: An Evolutionary View of Women's Reproductive and Sexual Functioning". Journal of Sex Research. 50 (3–4): 207–46. doi:10.1080/00224499.2012.763085. PMID23480070. S2CID30229421.