title: Women do not synchronize their menstrual cycles.
abstract: It is widely believed that women who live together or who are close friends synchronize their menstrual cycles. We reexamined this phenomenon in two ways. First, we collected data on menstrual cycles from 186 Chinese women living in dorms for over a year. We found that women living in groups did not synchronize their cycles. Second, we reviewed the first study reporting menstrual synchrony. We found that group synchrony in that study was at the level of chance. We then show that cycle variability produces convergences and subsequent divergences of cycle onsets and may explain perceptions of synchrony.
authors.affiliation: North Sichuan Medical College, Nanchong, People's Republic of China.
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Psychology, University of California, One Shields Ave., 95616, Davis, CA, USA. jcschank@ucdavis.edu.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Schank
keywords: Estrous synchrony; Human pheromones; Menstrual cycles; Menstrual synchrony; Reproductive synchrony