Menstruant as Zavah: How the Laws of Niddah Developed

Leviticus 15 describes two types of impure bleeding for women: menstruation (niddah), and bleeding that is “not during her menstrual period (zavah).” The Rabbis attempt to define the difference in an abstract manner, and in so doing, elide the two.

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Menstruant as Zavah: How the Laws of Niddah Developed

Tractate Niddah 1897 Vilna Printing 

Leviticus 15 lists various types of impurities based on male and female genital emissions:

Male — The text begins by describing an impure genital “flow” (zav) for men (vv. 2-15)—perhaps a kind of venereal illness, and then moves on to typical seminal emissions (vv. 16-18).

  • Zav (זָב; “flow”)
ויקרא טו:יב אִישׁ אִישׁ כִּי יִהְיֶה זָב מִבְּשָׂרוֹ זוֹבוֹ טָמֵא הוּא.
Lev 15:2 When any man has a discharge issuing from his member, he is unclean.[1]
  • Semen (שִׁכְבַת זָרַע)
ויקרא טו:טז וְאִישׁ כִּי תֵצֵא מִמֶּנּוּ שִׁכְבַת זָרַע וְרָחַץ בַּמַּיִם אֶת כָּל בְּשָׂרוֹ וְטָמֵא עַד הָעָרֶב.
Lev 15:16 When a man has an emission of semen he shall bathe his whole body in water and remain unclean until evening.

Whereas the impurity of the seminal discharge is short term, lasting only until the evening, and is removed simply by washing, the zav’s process requires counting seven days after the flow has stopped and washing specifically in “fresh” or “running” water [2](מים חיים). Following this, the man must bring an offering to the sanctuary and receive atonement (vv.14-15).

The difference between the process of purification for seminal emission and for zav emissions is likely due to the Torah seeing the former as normal and healthy and the latter as abnormal and unhealthy.

Female — The same division occurs in the description of female genital emissions (though presented in reverse order). The text first discusses menstruation (vv. 19-24) followed by a discussion of non-menstrual flow (vv. 25-30).

  • Menstruation (niddah, נִדָּה)
ויקרא טו:יט וְאִשָּׁה כִּי תִהְיֶה זָבָה דָּם יִהְיֶה זֹבָהּ בִּבְשָׂרָהּ שִׁבְעַת יָמִים תִּהְיֶה בְנִדָּתָהּ…
15:19 When a woman has a discharge, her discharge being blood from her body, she shall remain in her menstrual state seven days…
  • Non-menstrual flow
ויקרא טו:כה וְאִשָּׁה כִּי יָזוּב זוֹב דָּמָהּ יָמִים רַבִּים בְּלֹא עֶת נִדָּתָהּ אוֹ כִי תָזוּב עַל נִדָּתָהּ כָּל יְמֵי זוֹב טֻמְאָתָהּ כִּימֵי נִדָּתָהּ תִּהְיֶה טְמֵאָה הִוא.
Lev 15:25 When a woman has had a discharge of blood for many days, not at the time of her menstruation, or when she has a discharge beyond her period of menstruation, she shall be impure, as though at the time of her menstruation, as long as her discharge lasts.

As we saw with the two male discharges, purification from the woman’s menstrual period is described succinctly in the opening verse: the impurity ends after seven days, the length of a “standard” period (or a bit longer). Purification from an abnormal, and ostensibly unhealthy discharge, however, is more complicated:

ויקרא טו:כח וְאִם טָהֲרָה מִזּוֹבָהּ וְסָפְרָה לָּהּ שִׁבְעַת יָמִים וְאַחַר תִּטְהָר.
Lev 15:28 When she becomes pure of her discharge, she shall count off seven days, and after that she shall be pure.

As with the male flow, she must wait until the discharge ends, then count seven days with no discharge; only then she is pure. Following this, she must bring an offering to the sanctuary to receive atonement (vv. 29-30).

Prohibiting Sex with a Woman Experiencing Flow

As scholars have long noted, Leviticus 15 does not assume that sex with a woman during her period is forbidden, but this prohibition does appear in Leviticus 18:19 and 20:18. And as these texts in Leviticus 18 and 20 make no distinction between different types of vaginal bleeding, one may fairly assume that whether the woman is menstruating or experiencing some other type of bloody flow,[3] sexual activity would be forbidden. Certainly, this is what the rabbis assume.

Rabbinic Halakha: Niddah and Zavah

Rabbinic halakha distinguishes between the laws regarding menstruation (niddah) and those about non-menstrual bleeding, what the rabbis call zavah, i.e., “flow,” the feminine form of the biblical term for unhealthy male genital flow, zav.

To tease out the differences between these halakhot, the rabbis came up with a number of innovations:

Three Days of Bleeding – The verse says that a woman is a zavah (to use the rabbinic term) if she bleeds for “many days” (יָמִים רַבִּים). How many days is many days? Based on a midrashic analysis of the phrase, the rabbinic answer is three days (Sifra, Metzora, Zavim5:8-10).

What happens if she bleeds for only one or two days? Here the rabbis invented an entirely new category called “a woman who watches one day for one day” (שומרת יום כנגד יום; m. Niddah4:7, m. Zavim 1:1). In short, this means that she must wait one clean day before purification.[4] This is a radical departure from the biblical text, which knows nothing of such a category.

Purification at Night – Throughout the chapter, Leviticus 15 assumes that a person washes during the day and that evening becomes pure. The standard trope is “he shall wash in water and be impure until evening” (וְרָחַץ בַּמַּיִם וְטָמֵא עַד הָעָרֶב). When it comes to the menstruant woman, however, the text says, “she shall remain in her menstrual state seven days” (שִׁבְעַת יָמִים תִּהְיֶה בְנִדָּתָהּ).

Thus, the rabbis state that unlike all other impure people, a niddah only purifies herself (i.e., immerses in the mikvah) at night (j. Shabbat 2:1, Megillah 2:5; b. Niddah 67b).[5] A zavah, on the other hand, would go about purification in the standard way, and immerse during the day on the seventh day of her counting, and be pure that evening.[6]

11 Days – Although the Torah is clear that zavah bleeding is either “not during her menstrual period” (בְּלֹא עֶת נִדָּתָהּ) or “continues after her period is over” (אוֹ כִי תָזוּב עַל נִדָּתָהּ), it never clarifies how one determines the time of her “proper period” (called veset in rabbinic Hebrew) and when bleeding is outside this time frame.

One would imagine that the answer to this question would be simple; a woman would know, more or less, when she expects her period to start, and alternatively, when something feels different. Nevertheless, the rabbis do not leave this to individual intuition but claim that the eleven days following the seven days of menstruation delineated in biblical law are the days of zivah (i.e., non-menstrual flow; m. Niddah 4:4, 4:7, and 10:8).

The Mishnah simply takes this rule for granted,[7] and a number of later rabbinic texts quote the saying that “the eleven days between one niddah and the next are halakhah le-Moshe mi-Sinai” [8] (ואחד עשר יום שבין נדה לנדה הלכה למשה מסיני), but this a way of expressing a rule’s antiquity, not of explaining its origin.[9]

The Mysterious Eleven Days of Possible Zavah

The eleven-day rule is quite problematic, conceptually as well as empirically. It does not seem to correlate with any biological reality about menstruation, since the average woman’s cycle is closer to 28 days than 18 days.[10] The enigmatic “eleven-day” rule led to a sharp debate in the medieval period about what happens after this period ends and she has not had any bleeding.

18-Day Cycle (Maimonides)

In Maimonides’ understanding of the Mishnah, a woman’s cycle follows the pattern of 7 days of niddah – 11 days of zivah; 7 days of niddah – 11 of zivah, etc., starting from the day of her first period as a teenager (Mishneh Torah, Sefer Kedusha, “Issurei Biah” ch. 6:3-4; Kapih ed.):

כל שבעת הימים שנקבעה לה וסת בתחלתן הן הנקראין ימי נדתה, בין ראת בהן דם בין לא ראת. ומפני מה נקראין ימי נדה? מפני שהם ראויין לנדה וכל דם שתראה בהן דם נדה יחשב.
All seven days from when her first period was established are called “days of niddah,” whether she bleeds on them or not. Why are they called “days of niddah”? Because they are the days when her bleeding can define her as a niddah, and any bleeding she experiences on those days is considered niddah.
וכל אחד עשר יום שאחר השבעה הן הנקראין ימי זיבתה, בין ראת בהן דם בין לא ראת. ולמה נקראין ימי זיבה? מפני שהן ראויין לזיבה, וכל דם שתראה בהן דם זיבה יחשב. והזהר בשני שמות אלו שהם ימי נדתה וימי זיבתה.
All eleven days following the seven days are called the “days of zivah” whether she bleeds or not. Why are they called “days of zivah”? Because they are the days when her bleeding can define her as a zavah, and any bleeding she experiences on those days is consideredzavah. So be careful with these two terms, that is, “days of niddah” and “days of zivah.”
כל ימי האשה מיום שיקבע לה וסת עד שתמות או עד שיעקר הוסת ליום אחר תספור לעולם שבעה מתחלת יום הוסת, ואחריהן אחד עשר שבעה ואחריהן אחד עשר, ותזהר במנין כדי שתדע בעת שתראה דם אם בימי נדה ראת או בימי זיבה, שכל ימיה של אשה כך הן שבעה ימי נדה וי”א ימי זיבה…
All the days of a woman’s life, from the day of her first period till the day she dies or her period switches to a different day, she will count seven from the beginning of that (first) period, and afterwards eleven, seven, then eleven. Be careful with this counting, so that you can know when she bleeds whether it is occurring on her days of niddah or days of zivah, for this is how a woman’s life is: seven days of niddah and eleven days of zivah…

Considering the typical biological cycle of approximately twenty-eight days, this theory is unworkable, for how does this halakhic cycle map onto a biological cycle? For the average woman, every other menstruation would be considered irregular, zivah, bleeding with the consequent requirement for seven clean days, etc. Obviously, Maimonides is working with an abstract concept of niddah and zivah that bears very little relationship with the biblical juxtaposition of (normal) menstruation with (abnormal) non-menstrual bleeding.[11]

A Period of Potential Niddah

The majority of medieval scholars understood the eleven days as a restrictive category. That is, a woman’s bleeding is considered zivah only if it occurs during the first eleven days after a woman’s regular (i.e., biblical) “days of niddah.” Thus, any bleeding that occurs after this 18-day period is over is automatically considered the beginning of her next period (whether it is or not). This interpretation avoids forcing women to be zavot every other month, but it still makes little biological sense.

However the category of eleven days is understood, it has the effect of taking the determination of whether she is menstruating or whether something is wrong out of the woman’s hands and of putting it into an artificial rubric of counted days.

The Problem of Keeping Track

Given that the laws of purification for niddah and zivah are quite different, and that until she is purified, the couple’s sexual activity must be curtailed, one might imagine that figuring out where a given woman is in her 7-11 cycle would have been a high priority for a married couple and the rabbis who would advise them. It would seem that early on, the rabbis, and those Jews who followed their rulings, were having trouble with this system of counting.[12]

For instance, the Babylonian Talmud recounts the following tradition (b. Niddah 66a):

אמר רב יוסף אמר רב יהודה אמר רב, התקין רבי בשדות: ראתה יום אחד – תשב ששה והוא, שנים – תשב ששה והן, שלשה – תשב שבעה נקיים.
Rav Joseph said in the name of Rav Yehudah, who in turn said in the name of Rav: “Rabbi [Judah HaNasi] enacted in sadot (“rural communities” or possibly the name of a town): If a woman bleeds for one day, she should count that day plus six more. If she bleeds for two days, she should count those two days, plus six more; if she bleeds for three days, she should sit for seven “clean” (days)[13] [after the bleeding stops].”

According to this account, Rabbi Judah HaNasi assumed that women in rural communities (or in the community of Sadot) could not keep track of their periods, at least not the way the rabbis define them, and thus, he created a new rule for them: Every bleeding is treated as if it is both niddah and zivah.

The most significant aspect of this rule is that whenever a woman bleeds for three days – which is almost certainly going to be the case for every period – she must wait seven “clean” days after the bleeding ends before purifying herself in a mikvah, as if she were also a zavah. Not only does this go against the letter and spirit of the biblical law, but it creates serious hardship for the couple. But this, apparently, was the cost of complex and artificial interpretation of the verses offered by the rabbis.[14]

Treating Even a Drop of Blood as Both Niddah and Zavah

The next line of this passage offers an even more extreme example of eliding the two types of bleeding (b. Niddah 66a):

אמר ר’ זירא: בנות ישראל החמירו על עצמן, שאפילו רואות טפת דם כחרדל – יושבות עליה שבעה נקיים.
Rabbi Zeira said: “The ‘daughters of Israel’ imposed a stringency upon themselves that they would wait out seven clean (days) even if they saw a drop of blood the size of a mustard seed only.”[15]In this version of the practice, every bleeding, no matter when or for how long, is automatically treated as if the woman were both a niddah and a zavah.

The Custom of Jewish Women?

The most intriguing aspect of this “report” is that it is not about the legislation of a rabbi, as we saw in the above statement about Rabbi Judah HaNasi, but is attributed to the initiative of women themselves. If the attribution of this shift in practice to women is accurate, which is unknown,[16] why would women choose to do so?

Perhaps, as we saw with the tradition about R. Judah HaNasi, the women were simply concerned about miscounting their cycles, since according to rabbinic law, their cycles would be determined by the artificial cycle of 7- and 11-day periods of time.

And yet, another advantage of eliminating the distinction between niddah and zivah is that by circumventing the complex and rabbinic system and going with a “one size fits all”niddah/zivah for every period, the woman would no longer be dependent on consultation with a rabbinic sage.

Why So Strict?

The advantages of eliminating the distinction between niddah and zivah could only be accomplished by adding more days to a woman’s monthly calendar where she and her husband are forbidden from being intimate. Perhaps (some) women may simply have felt that the extra pious way is the safest way to avoiding accidental transgression. In addition, it is possible that some of them may have been more than happy to restrict their own sexual accessibility to their husbands beyond the biblical limit, or at least, weren’t bothered by doing so.

The Return of the Niddah and Zavah Distinction in Modern Times

Whatever its reason and origin, this practice of eliding niddah and zavah became the norm in Jewish law and is codified by all the standard medieval halakhic works, including the Shulchan Arukh (Yoreh Deah, 183:1).[17] Nevertheless, modern times have seen some pushback in certain communities, whether because of cases of halakhic infertility[18] or because modern couples find the extension of abstinence too much of a hardship.[19]

Thus, some observant Jews have decided to return to a form of “biblical law,” towards a “friendlier” form of sexual discipline. And yet, this biblical observance remains rabbinic in nature since all the details of hilkhot niddah, such as the definition of zavah as three days, the eleven days of zivah, and even requirement of purification through mikvah,[20] are all based on rabbinic interpretation and not the Bible itself.

View Footnotes

Published 2018-04-18

  1. The text goes on to explain in more detail what it means by flow:

    ויקרא טו:ג וְזֹאת תִּהְיֶה טֻמְאָתוֹ בְּזוֹבוֹ רָר בְּשָׂרוֹ אֶת זוֹבוֹ אוֹ הֶחְתִּים בְּשָׂרוֹ מִזּוֹבוֹ טֻמְאָתוֹ הִוא.
    Lev 15:3 The impurity from his discharge shall mean the following — whether his member runs with the discharge or is stopped up so that there is no discharge, this is his impurity.
  2. ויקרא טו:יג וְכִי יִטְהַר הַזָּב מִזּוֹבוֹ וְסָפַר לוֹ שִׁבְעַת יָמִים לְטָהֳרָתוֹ וְכִבֶּס בְּגָדָיו וְרָחַץ בְּשָׂרוֹ בְּמַיִם חַיִּים וְטָהֵר
    Lev 15:13 When one with a discharge becomes clean of his discharge, he shall count off seven days for his cleansing, wash his clothes, and bathe his body in fresh (or “running”) water; then he shall be clean.
  3. The language of the Torah assumes blood as the representative female genital fluid also for the non-menstrual flow (15:25).

  4. In the Amoraic period, this receives the name “small zavah” (זבה קטנה) while zavah gets called “great zavah” (זבה גדולה). Tannaitic sources do not use this terminology. 

  5. The rabbis also include a woman who gives birth in the niddah category for this purpose.

  6. Biblically speaking, no ritual of washing or purification is listed for either of these women, but for various reasons, the rabbis assume that she must immerse in a mikvah. See discussion in my, “Niddah (Menstruation): From Torah to Rabbinic Law,” TheTorah.com, (2018). See also Zev Farber, “The Purification of a Niddah: The Torah Requirement,” TheTorah.com(2014); Yitzhaq Feder, “The Purification of a Niddah: The Legal Responsibility of a Reader,”TheTorah.com (2014); Isaac Sassoon, “The Purification of a Niddah: When Silence Matters,”TheTorah.com (2014). 

  7. When the Mishnah says (Niddah 4:7) that “during the entire eleven days she is presumed to be pure,” it projects that it is known what these eleven days refer to. 

  8. The Jerusalem Talmud says this in the name of Bar Kappara (j. Berakhot 5:1). The Sifraand the Babylonian Talmud cite it in the name of Rabbi Eleazar ben Azariah quoting Rabbi Akiva (Sifra, Tzav, 6:11.6; b. Niddah 72b, b. Menachot 81a).

  9. [9] Editor’s note: For a discussion of this and other “from Sinai” claims in rabbinic literature, see Yoseif Bloch, “Trusting in the Process of Torah Mi-Sinai,” TheTorah.com (2016).

  10. This problem was noted explicitly by Rashbash (R. Solomon ben Simon Duran, 1400-1467), who argues in a responsum (#513b) that the length of women’s cycles must have changed over the years, since in his days, the zivah period should be 14 days not 11. Biologically speaking, this shifting of cycle lengths must be considered a fanciful suggestion, but it underscores the empirical problem: as a rule, women do not have 18-day cycles. One elegant solution suggested by David Steinberg (personal communication) might be that it is based on the simple mistake of confusing eleven and twenty-one, but that seems unlikely, since no manuscript and no text in the halakhic literature ever offers this possibility.

  11. This was not how Maimonides understood the niddah/zivah cycle in his earlier years (see his commentary on the Mishnah, Niddah 4:7). Apparently, his view changed when he came in contact with Geonic responsa (such as that of Rav Sherira) on this topic which advocated for the rigid 7-11 cycle (see Joseph Kapih’s commentary on the Mishnah Torah, ad loc.). 

  12. And I am not even taking into account the interruption of birth and pre- and post-partum bleeding, or the question about what kind of discharge counts as blood – all of which complicate the calendar even further.

  13. The reference to these days of not bleeding as “clean days” appears for the first time in the talmudic discussions only, adding a connotation of hygiene to what until then was articulated in ritual terms. This unfortunately becomes much more pronounced in medieval halakhic literature. Another locution that appears (only once) in the Babylonian Talmud isyemei libun, the days of whitening. It is found in the pietistic story of the pious scholar who died young, because as it turns out he shared his bed with his wife during the days following her actual yemei niddah. Rashi interprets it to mean that she is wearing white (b. Shabbat13b, with Rashi ad loc.)

  14. Maimonides writes that “in the days of the gemara this matter of blood-flows became ridden with doubts, and the menstrual periods (vastot) disarranged.” Mishneh Torah,Hilkhot Issurei Bi’ah 11:3. In his view it is because of human limitations, not only the women’s, but the rabbinic sages’ also, who had a difficult time to distinguish different kinds of bleeding when consulted, that the practice changed. The rabbinic sages themselves also became subject to confusion by the account of the Talmud itself, because not all sages understand how to properly distinguish between different kinds of genital bleeding, some which may or may not be subject to the impurity of niddah.

  15. Also cited on b. Berachot 31a-b, b. Megillah 28b and elsewhere in rabbinic literature. In the Yerushalmi, this is formulated as a rule attributed to Rav Huna, rather than as a shift in women’s practice (j. Berakhot 5:1, 8d).

  16. There are so few practices whose origin is attributed to women in the Talmud that every time they are, one must at least wonder why this would be the case, especially as the practice is reported by one of the talmudic scholars themselves. Some feminist scholars have suggested that the talmudic sages here may have attributed the shift in practice to women in order to make it more persuasive to them, e.g., Judith Hauptman, Rereading the Rabbis: A Woman’s Voice (Boulder: Westview Press, 1998), 158. Others have suggested that the phrase benot yisrael is predominantly used in the context of ritual innovation, allowing us to consider women as ritual agents, rather than mere recipients of the halakhic process, e.g., Mika Ahuvia and Sarit Kattan Gribetz, “‘The Daughters of Israel’: An Analysis of the Term in Late Ancient Jewish Sources,” Jewish Quarterly Review 108:1 (Winter 2018): 20.

  17. Maimonides writes that “everyone, in every place where are Jews, observes this minhag (custom).” (Hilkhot Issurei Bi’ah, 11:3).

  18. This refers to women who ovulate after the seven-day period is over but during their seven “clean” days, before they go to the mikvah.

  19. See, Daniel Rosenak, To Restore Purity to Its Former Splendor (Tel Aviv: Yedioth Ahronoth, 2011 [Hebrew]), and even earlier, Blu Greenberg, On Women and Judaism: A View from Tradition (Philadelphia: Jewish Publication Society, 1981), 121. See also the responsa in the Conservative Movement, pushing to abolish treating niddah as zivah: Susan Grossman, “Mikvah and the Sanctity of Being Human,” CJLS (2006); Avram Israel Reisner,“Observing Niddah in Our Day,” CJLS (2006); Miriam Berkovitz, “Reshaping the Laws of Family Purity for the Modern World,” CJLS (2006).

  20. Indeed, by insisting on ritual purification of any type, they are mixing Leviticus 15, concerning sanctuary impurity, with the sexual prohibitions of chapters 18 and 20.