Shavout 18b ~ The regularity of the menstrual cycle

שבועות יח, ב

ת"ר "והזרתם את בני ישראל מטומאתם" אמר רבי יאשיה מיכן אזהרה לבני ישראל שיפרשו מנשותיהן סמוך לוסתן וכמה אמר רבה עונה 

Our Rabbis taught: "You shall separate the children of Israel from their uncleanness"[Lev. 15:31]; R.
Yoshiah said: From this we deduce a warning to the children of Israel that they should separate from
their wives near their periods. And how long before? Rabbah said: One ‘onah [either the whole day or the whole night].

From here.

In tomorrow's page of Talmud, Rabbah (~270-330 CE), who lived in Babylonia, ruled that a couple must refrain from intercourse if menstruation is expected to begin within a twelve hour window.  This ruling is included in the Shulchan Aruch, the code of Jewish Law, as the required Jewish practice:

שולחן ערוך יורה דעה קפד, ב

בִּשְׁעַת וִסְתָּהּ, צָרִיךְ לִפְרֹשׁ מִמֶּנָּהּ עוֹנָה אַחַת, וְלֹא מִשְּׁאָר קְרִיבוּת אֶלָּא מִתַּשְׁמִישׁ . אִם הוּא בַּיּוֹם, פּוֹרֵשׁ מִמֶּנָּהּ אוֹתוֹ הַיּוֹם כֻּלּוֹ אֲפִלּוּ אִם הַוֶּסֶת בְּסוֹפוֹ, וּמֻתָּר מִיָּד בַּלַּיְלָה שֶׁלְּאַחֲרָיו, וְכֵן אִם הוּא בִּתְחִלָּתוֹ, פּוֹרֵשׁ כָּל הַיּוֹם וּמֻתָּר כָּל הַלַּיְלָה שֶׁלְּפָנָיו

During her veset, [the expected onset of menstruation, her husband] must separate from her for one onah, not from all contact but only from marital relations. If her period is expected in the daytime, separate from her for that entire day, even if the veset is at the end of the day, and it is permitted [to have marital relations] immediately the following evening. Similarly, if [the veset] is at the beginning, separate the whole day and it is permitted the entire preceding evening...

This ruling suggests that women can predict when the onset of menses will be. How often is that in fact the case? Well, for the half of you who are men, it might surprise you to learn that this ability to predict the onset is less common than you would think. Women, I am sure, already know this.  

How Regular is Regular?

In a 2011 review paper "The normal menstrual cycle in women," the authors point out that the 28 day"text-book" length of the menstrual cycle in young healthy women is in fact highly variable. Even between similarly aged women the cycle may range from 25 to 34 days. More to our topic, there are many women in whom the cycle length changes. In those aged around twenty, about 47% of women have a variation by as much as 14 days annually.  

Variation of menstrual cycle length as a function of age in the woman. This graph shows mean cycle length and the range (5th and 95th percentile) reported in 4 studies. yrs = years, d = days. Triangles indicate the age group in which the indicated percentage of women shows more than 14 days variation in cycle length annually. From M. Mihma, S. Gangooly, S. Muttukrishnab. The normal menstrual cycle in women. Animal Reproduction Science 124 (2011) 229–236.

Another study on the variability of menstrual length from one cycle to the next comes from the Obstetrics and Gynecology Department at the University of Pittsburgh.  They asked 130 women to keep menstrual diaries and record their menstrual flow for at least four menstrual cycles and for as long 30 weeks. 

“Participants prospectively recorded their menses for the up to 30 weeks. Each subject’s estimated cycle length was compared to the average of her actual cycle lengths and the range and variability in each individual’s cycle length was calculated. A total of 786 cycles from 130 women who recorded 4 or more cycles were analyzed.”

They found that 46% of all subjects had a cycle range of 7 days or more, and 20% had a cycle range of 14 days or more. In other words, almost half of the women had a cycle-to-cycle change of at least a week, and one in five had a change of two weeks or more.  "Therefore" they wrote, "one out of every five subjects who reported that they had regular cycles were experiencing periods that occurred 1 week away from the expected date."

Irregularity in Jewish Law

For those who wish to learn more, there is a long section in the Shulchan Aruch (יורה דעה הל׳ נידה  קפט) that addresses the complicated issue of irregular menses and the required time for a husband and wife to refrain from intercourse. This long section is needed because for many (?most) women, the length of the menstrual cycle changes from one period to the next. R. Yoshia's ruling that a couple must refrain from marital relations "סמוך לוסתן"  - at the expected time of menstruation -  turns out to be a rather complicated thing to do.  

“This study establishes that “regular” menstrual cycles are quite variable from cycle to cycle. The inherent variability in menstrual cycle length, which is likely a function of when ovulation occurs, must be studied prospectively to understand its full impact on contraceptive research trials and pregnancy-related care.”

— Crenin, M.D. Keverline, S. Meyen, L.A. How regular is regular? An analysis of menstrual cycle regularity. Contraception 2004:70;289-292

Sotah 20b ~ Queen Esther, Mood, and Menstruation

There is a great deal of scientific work investigating the effect of the menstrual cycle on a women's mood. There has been less examination of the effect of mood (or stress) on the cycle.  In today's page of Talmud, there is a digression into gynecology and psychology, and specifically the role of psychological stress on menstruation.  

Queen Esther's Stress

סוטה כ, א

למימרא דבעיתותא מרפיא אין דכתיב ותתחלחל המלכה מאד ואמר רב שפירסה נדה והא אנן תנן חרדה מסלקת דמים פחדא צמית ביעתותא מרפיא

Does fright loosen the womb [and causes a woman to menstruate]? Yes, as the verse states (Esther 4:4) "...and the Queen [Esther] became very afraid" about which Rav explained:" she began to menstruate."

But haven't we learned elsewhere in a Mishnah (Niddah 39a) that fear suspends the discharge of menstrual blood? In fact, fear that is not sudden contracts [the womb and prevents bleeding], but sudden fear loosens [the womb and causes early menstrual bleeding].

Here are some of the things that the rabbis of the Talmud believed could induce menstruation:

1. Carrying a heavy load (Tosefta Niddah 9:1)

2. Jumping (ibid)

3. Sudden fright (Niddah 71a, and Niddah 39a)

4. Yearning for intercourse (Niddah 20b)

5. Garlic, onions and peppers (Niddah 63b)

In today's daf, Rav opined that fear can induce menstruation. Let's take a look at the medical literature and see whether or not it supports his assertion.

“Data from both animal and human research indicate that psychological stress is associated with altered menstrual function.”

— Barsom S, et al. Association between psychological stress and menstrual cycle characteristics in perimenopausal women. Women’s Health Issues 14 (2004) 235-241

The Effect of Stress on Menstrual Function

In a review from the Department of Biological Sciences at Ohio University, researchers acknowledged that stress is difficult to define. However, one final common pathway of stressors is the low availability of dietary energy. Ovulation - which is the first part of the cascade that leads to menstruation - has been blocked in hamsters "by food restriction, pharmacological blockers of carbohydrate and fat metabolism, insulin administration (which shunts metabolic fuels into storage), and cold exposure (which consumes metabolic fuels in thermogenesis)." Women athletes frequently experience a lack of menstruation, which is found in up to 65% of competitive young runners. But what about psychogenic causes of a disturbed menstrual cycle - after all, Rav taught that it was fear that caused Esther's presumably early onset of menstruation? While not adressing this directly, the Ohio University researchers had this to say about the relationship between psychological stressors and amenorrhea (the lack of menstruation. Remember that word - it will come up again):

Associations between psychological disturbances and amenorrhea or infertility have long been interpreted as a causal relationship, but prospective studies demonstrating that psychogenic factors contribute to reproductive dysfunction in women are almost completely lacking . Early psychoanalytic conclusions that psychological conditions underlie involuntary infertility in women have been criticized recently on several grounds: first, the same psychological conditions have been found in analyses of fertile women; second, other women with very serious psychic problems conceive with ease; and third, couples with an unfulfilled desire for a child do not show psychological disorders any more frequently than do couples without fertility disorders. Even the direction of causality is questionable, because there are grounds for believing that infertility and its medical treatment cause the depression and anxiety observed in some infertility patients. These findings have led to the recommendation that the term ‘psychogenic infertility’ should be withdrawn from use because it is simplistic and anachronistic.

Menstruation and Incarceration

Some of the rabbis viewed Esther's association with King Achashverosh as being coerced: she was brought to his palace against her will, and remained there in a similar state. So with only a bit of a stretch, we might turn to a 2007 paper published in Women's Health Issues which addressed the influence of stress on the menstrual cycle among newly incarcerated women.  Researchers analyzed 446 non-pregnant women who answered a number of detailed questions about their menstrual cycles.  They found that 9% reported amenorrhea (I told you what that meant two paragraphs ago) and that a third reported menstrual irregularities.  

“Incarcerated women have high rates of amenorrhea and menstrual irregularity and the prevalence may be associated with certain stresses. Further research on the causes and consequences of menstrual dysfunction in this underserved population is needed.”

— Allsworth J. et al. The influence of stress on the menstrual cycle among newly incarcerated women. Women's Helath Issues 2007; (17) 202-209.

As might be expected, the stressors of the incarcerated women in this study included drug and alcohol problems and sexual abuse. These are not the same stressors that faced Queen Esther - who was held in such esteem by her kingly husband that he promised her (Esther 5:6) "up to half of the kingdom."  But this work does show how stress may impact the menstrual cycle.  

A Longitudinal Study of Psychological Stress and Menstruation

The final study we will review comes from a cohort of predominantly white, well educated married women of whom 505 were "invited to participate join a special survey focusing on midlife and menopause." Rather than ask about stress and current menstruation, the researchers performed a two-year analysis. Here's what they found:

In analyzing stress levels and cycle characteristics across 2 years...women with marked increases in their level of stress (n 􏰸=30) are shown to have decreased length (􏰿0.2 days/cycle) of menstrual cycle intervals and decreased duration of bleed (􏰿0.1 day/cycle) compared with increases in these measures (􏱀2.9 days/cycle for cycle interval; 􏱀0.3 days/cycle for duration of bleed) among women with no marked change in stress level (n 􏰸=103); t-tests indicate that these differences are significant (p < .05).

Some of the differences that the researchers found in this group were really small - "0.3 days/cycle for duration of bleeding" but if you are into statistics this difference can be significant (that's what those t-tests are all about). But these statistical associations were not powerful, and the researchers concluded that "the results of this investigation...suggest that, in the long term, stressful life events have little relationship to the length of menstrual cycle intervals and the duration of menstrual bleeding in perimenopausal women."

The three studies we've reviewed (even that last one with its weak findings) all suggest that there is indeed some relationship between psychological stress and menstruation.  Generally, the effect of stress is to increase the length of the menstrual cycle which may result in amenorrhea.  But according to Rav, stress caused Esther to menstruate sooner - the opposite of most modern research findings.  Single events should be used with caution when trying to build a general explanatory model, but Rav, and the other rabbis of the Talmud were onto something when they noted that both acute and chronic fear (which is of course just one type of stress) -  can effect a women's menstrual cycle.