Do Women's Periods Genuinely Synchronise When They Live Together?
A 1971 study claimed that the dates of housemates periods move, then align but that long-held belief is being challenged by proof and new studies
You know what happens when women live together. They start to menstruate together. Suddenly everyone craves chocolate and runs out of tampons at the same time. Not only that, but the chosen cycle often seems to belong to the most assertive female. Well thats biology for you it must be pheromones or the lunar cycle or something. Evolutionary anthropologists have suggested that synchrony would prevent any one female being monopolised by a single dominant male.
Ever since Martha McClintock, a psychologist from Harvard University, published her 1971 study of 135 female undergraduates living in a college dormitory together, it has been an accepted truth that menstrual cycle synchronise when women live together. Her study, based on an analysis of about eight cycles per female, found that roommates and close friends saw the average number of days between the beginning of their periods fall from eight or nine to five days.
A control group of randomly chosen females had cycles that remained 10 days apart from each. A study in 1999 found that 80% of women believed in the synchronising phenomenon with 70% saying that it was a pleasant experience. Its a powerful concept after all that the empathy of women can make their periods fall in line. But is it really true?
The answer
Well if you are one of the 80% of women who believes in synchronicity brace yourself. It isnt a thing. Since McClintocks analyze there has been enough research with negative results to move menstrual synchronicity into urban mythology. Many studies have tried to replicate McClintocks findings some have succeeded, but more have not.
Criticisms of McClintocks work include statistical mistakes not controlling for chance in the results and inflating the initial differences in the onset of menstrual cycles that led to synchronicity being over stated.
A study of Dogon women in west Africa, who were segregated into menstrual shacks, find no synchronicity over 763 days and no effect of the moon on periods( and these were ideal test conditions, as there was no electricity ).
A study of 186 women in China who lived together for a year also find no synchronicity. But the researchers pointed out that the start of periods differed for women, and cycles were often variable, which could give the false impression of synchronicity. Menstrual cycles can differ from between 21 to 35 days. Stress, weight loss or illness will all interrupt periods. A study of 26 lesbian couples find no synchronicity but did find individual menstrual cycle varied by up to 10 days. So despite the internet refusing to let this myth die you are the owner of your menstrual cycle and no friend, however close, can control it.
Read more: www.theguardian.com
Do Women's Periods Genuinely Synchronise When They Live Together?
Do Women's Periods Genuinely Synchronise When They Live Together?
Do Women's Periods Genuinely Synchronise When They Live Together?
Do Women's Periods Genuinely Synchronise When They Live Together?
Do Women's Periods Genuinely Synchronise When They Live Together?