Do menstrual cycles synchronise?
There is no simple answer to this question. The suggestion that menstrual cycles synchronise was first published in 19711 by Martha McClintock. Since then, several studies have been conducted to replicate the findings, with some failing2 and some succeeding3 to do so. According to a 2017 pilot study4 conducted by a period-tracking app company, cycles are actually less likely to sync as time progresses. Mathematical analyses have suggested that overlap of menstrual cycles is just a case of statistical probability.
To learn more, read this 2017 article5 by Oxford associate professor Alexandra Alvergnes.
References:
- McClintock, M. (1971). Menstrual Synchrony and Suppression. Nature, 229.
- Ziomkiewicz, A. (2006). Menstrual Synchrony: Fact or Artifact? Human Nature, 17(4), pp. 419-432.
- Weller, A. & Weller, L. (May, 1993). Menstrual synchrony between mothers and daughters and between roommates. Physiology & Behavior, 53 (5), pp. 943-949.
- Clue Period Tracker (2016). Do menstrual cycles sync? Unlikely, finds Clue data.
- Alvergne, A. (July 14, 2016). Do women’s periods really synch when they spend time together? The Conversation.