Menstrual Synchrony...In Ancient Egypt?


Some of the Ways Menstrual Synchrony Is Being Used to Interpret the Past



In 1999, Terry G. Wilfong published a paper, “Menstrual Synchrony and the “Place of Women” in Ancient Egypt (OIM 13512).”  To begin deciphering this paper title, “Place of Women” refers not to sociopolitical status, but to an actual physical space.  “OIM 13512” refers to an ostracon owned by the Oriental Institute Museum.  An ostracon is a fragment of clay pottery. 


OIM 13512 is believed to be from “the site of Deir el-Medina or nearby” and the text on it is dated “at around 1204 B.C.[E.] (Merneptah) or 1173 B.C.[E.] (Ramessides III).  Twilfong states:


“The basic sense of the text is clear:  Eight women who were menstruating came out of the village on their way to or from a location called the “place of women.”


“Hsmn” is used in OIM 13512 to denote menstruation; Twilfong reasons that similarly, in “a lengthy roster of absences by individual workers” to be found on ostacon O. BM 5634, “hsmn” has the same meaning, that is, “menstruation.”  Twilfong explains:


“In nine cases, the absence of a worker is ascribed to the hsmn of his wife or only one case in O. BM 5634 is a man absent more than once for the same woman’s hsmn...and in only one case is a man absent for the hsmn of more than one female relative...”


Twilfong argues that these absences might be due to menstruating women going to “the place of women”, or perhaps experiencing “incapacitating” dysmenorrhea, thus requiring the worker to take the female relative’s place in the household that day.


Twilfong then goes on to project “probable” menstrual cycle onsets backwards and forwards in time, from the dates of the workers’ absences listed in the roster; and concludes:


“The periods of four of the women fall within a few days of each other over most of the year; while the other three have secure synchrony [sic] in the earlier part of the year.  Nefrobe’s wife has periods near the time of the first group of the four women, while Sibe’s wife is the only one of the group who seems not to have synchronized.”


Hopefully, MOLT visitors, having read (and perhaps struggled) through previous sections of this MOLTXIBIT, recognize a number of problems with Twilfong’s reasoning:


A)  “Calculating” menstrual cycles based on ONE possible onset date in the case of eight of the workers, and TWO possible onset dates in the case of one worker.  Remember, “hsmn” is translated to mean “menstruation” or “menstruating,” NOT “onset of bleeding days.”  From the absence roster themselves, we cannot tell whether workers were taking time off for the first, second, third, fourth or fifth day of a female relative’s period.


B)  Assuming that we did know with certainty that the dates in the absence roster referred to cycle onsets, even Weller and Weller believe that at least three sets of cycle onsets must be recorded in order to test for menstrual synchrony.  Schank, Strassmann, and others believe that an even greater number of cycle onsets must be collected, as cycles whose periods are noninteger multiples of each other slowly diverge and converge over time.


This problem of synchrony being impossible for menstrual cycles whose periods are noninteger multiples of each other holds true for ancient Egyptian women.  Twilfong does not explicitly state how she calculated “probable” cycle lengths (although it is easy enough to determine that “29.33” is 88/3 for Simut’s wife).  A 29.33 cycle length cannot, for example, synchronize with a 28-day cycle.  They will fall in and out of “synchrony.”  


Even if the meaning of synchrony is redefined to mean that cycles are less “out of synch” than predicted (and thus in a state of hypodivergence, not synchrony), you would still need a great number of cycle onsets to determine this.


C)  As we do not know the age of the women involved, we certainly don’t know the “probable” degree of cycle length variability.  That is, although it may be as simple as dividing 88 days (the length of time between two absences for Simut) by 3 (thus, 29.33 days) to determine the length of Simut’s wife’s menstrual cycle, if she were still postmenarchal, it may be that she had FOUR 22-day cycles (88/4 = 22), or conversely, if she were perimenopausal, perhaps she only had TWO 44-day cycles (88/2).  Take a look back at the Treloar Variability Graph for a better understanding of this point.


D)  Based on the small amount of data available to us from O. BM 5634, it is not possible to even begin to distinguish between menstrual synchrony and menstrual overlap.  Try going back and reading through the quotes from Twilfong’s paper, replacing “synchrony” with “overlap.”  Does it make the discussion of O. BM 5634 seem less emotionally compelling or interesting?  Why is “synchrony” automatically more interesting than “overlap?”


But there’s more.  Twilfong states:


“If the cycles recorded in O. BM 5634 are projected ahead through calculation, a larger possible pattern emerges.  The dates of menstruation recorded in OIM 13512..., O. Cairo 25782..., and O. Cairo 25784...all fall within 3-7 days of the expected dates from one of the two synchronous [sic] cycles attested to in O. BM 5634.  While there is far too much potential for variation to be certain, it may be possible from this correlation that the Deir el-Medina records attest to some sort of menstrual synchrony continuing among its female population for over forty years.”

WOW!  MOLT will let Beverly Strassmann (also a professor, like Twilfong, at the University of Michigan), have the last word, from Strassmann’s 1999 paper, “Menstrual Synchrony Pheremones:  Cause for Doubt,” an Opinion in the journal Human Reproduction:


“Popular belief in menstrual synchrony stems from a misperception about how far apart menstrual onsets should be for two women whose onsets are independent.  Given a cycle length of 28 days (not the rule -- but an example), the maximum that two women can be out of phase is 14 days.  On average, the onsets will be 7 days apart.  Fully half the time they should be even closer (Wilson, 1992; Strassmann, 1997).  Given that menstruation often lasts 5 days, it is not surprising that friends commonly experience overlapping menses, which is taken as personal confirmation of menstrual synchrony.”


Now let’s take a look even further back in time!

X Menstrual Synchrony Among Early Humans?

X Menstrual Synchrony Index

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