Niddah and Zivah: Counting Days and Establishing Purity

Niddah and zavah describe different halachic statuses arising from uterine bleeding. Dam hakoshi is bleeding associated with labor pains; its particular laws are explained in Chapter 7. Blood associated with childbirth includes bleeding during the initial period of impurity. Dam tohar, “blood of purity,” refers to bleeding during the subsequent period that the Torah treats differently, as discussed in Chapter 4.

These names identify legal categories. They do not indicate that the blood necessarily comes from different bodily sources.

The distinction depends on when the bleeding occurs within the periods defined by the Torah. Blood from the same source can therefore have different consequences during the days of niddah, the days of zivah, or the periods associated with childbirth. Each category remains subject to its own conditions; the detailed rules concerning labor and childbirth follow later.

A veset is an established time for the onset of bleeding, such as a recurring calendar date or interval. At the initial onset described here, the seven-day niddah period begins. An early end to the bleeding does not shorten that period, and continued bleeding during it does not restart the seven-day count.

In the continuing reckoning explained below, bleeding is classified according to whether it occurs during the designated days of niddah or zivah. A new sighting of blood does not automatically begin a new reckoning.

These are seven days of niddah, not seven clean days. Under the framework being described, they can include days on which bleeding continues. Permission to resume marital relations also requires valid immersion after the required period; the passage of seven days alone does not make her permitted.

The eighth day belongs to a different halachic category, even if the bleeding continues without interruption from the preceding days. The expression “outside the time of her niddah period,” drawn from Vayikra 15:25, refers here to the Torah’s defined periods rather than simply to bleeding that seems medically irregular.

Bleeding on this one day does not by itself make her a zavah gedolah, a major zavah. The distinctions between one, two, and three consecutive days of zivah bleeding are explained in Halachos 7–11.

The preceding halachah identified bleeding on the eighth day as zivah. This halachah extends that classification to the entire intervening zivah period.

A halachah leMoshe miSinai is a law received through the Oral Tradition from Moshe at Sinai. Here, that tradition establishes an eleven-day interval following the seven days of niddah. Counting from the beginning of the seven-day period, days 8–18 are the eleven days of zivah.

This is a halachic classification of days. It does not mean that a woman must physically menstruate every eighteen days. The Rambam’s continuing reckoning is explained in Halachah 6.

The name belongs to the designated seven-day period in the reckoning. Those days retain their classification even when no bleeding occurs. Calling them “days of niddah” does not, by itself, mean that a woman who has seen no blood becomes impure.

The distinction is between the classification of the days and the woman’s actual status. “Days of niddah” identifies the kind of bleeding those days can produce: if qualifying bleeding occurs during them, it is classified as niddah blood rather than zivah blood.

Like “days of niddah,” this name identifies a period in the reckoning; it does not by itself make her a zavah.

Blood seen during this eleven-day interval is governed by the laws of zivah. The number of consecutive days on which bleeding occurs determines whether she becomes a minor or major zavah, as explained beginning in Halachah 7.

The chapter’s later rulings depend on keeping these periods distinct. The terms identify when bleeding occurs; they do not simply describe how long she has been bleeding or whether she has already completed purification from an earlier episode.

The end of the eleven-day interval does not itself remove impurity already incurred. The required purification must still be completed.

According to the Rambam’s reckoning here, the designated periods continue in a repeating pattern: seven days of niddah, followed by eleven days of zivah. The count continues even when no bleeding occurs. A later sighting is classified by its place within that reckoning; it does not automatically begin a new seven-day period.

The designated periods classify bleeding; as explained above, their arrival alone does not create impurity.

The classification determines which purification rules apply when bleeding occurs. Childbirth can interrupt this reckoning; the resulting calculation is explained in Chapter 7, Halachah 2.

Counting guide

Days 1–7: the seven days of niddah.

Days 8–18: the eleven days of zivah, numbered 1–11 within that interval.

Day 19: the beginning of the next niddah period.

In Halachos 16–18, “the twelfth day” means the day following the eleven-day zivah interval. It is the first day of the next niddah period, not a twelfth day of zivah. In Halachah 19, the first case counts from the beginning of niddah; the second counts within the zivah interval.

“Minor” describes the extent of her zivah status, not her age. A zavah ketanah ordinarily must observe one clean day following the bleeding before completing the purification process described below. The expression shomeres yom keneged yom names this requirement. Even after two consecutive bleeding days, one clean day is sufficient under this framework.

The special rules for bleeding at the end of the eleven-day zivah period are explained in Halachos 17–18.

All three consecutive bleeding days must fall within the days of zivah. Three consecutive days of bleeding do not establish major-zavah status if one of them belongs to the days of niddah, as explained later in Halachah 16.

The plural “days” already indicates at least two. The additional word “many” establishes a minimum of three for the full zavah status discussed here.

“Clean days” are days free of the uterine bleeding that would invalidate the count. A major zavah needs seven consecutive clean days; a minor zavah ordinarily needs one. The immersion requirements and the time at which marital relations become permitted are explained in the following halachos.

A major zavah brings her offering on the eighth day, following the seven clean days. After the required immersion and completion of the seventh clean day, however, she may resume marital relations that evening; she does not have to wait until the offering is brought. The offering belongs to the further purification requirements explained in Hilchos Mechusrei Kapparah, Chapter 1.

The shorter purification process of a minor zavah does not mean that relations with her are permitted while she remains impure. The distinction concerns what she must do to become purified, not whether the prohibition applies.

A halachic day begins at night. Bleeding anywhere within that night and the following daytime makes it a bleeding day for this reckoning. Even if the bleeding stops quickly, the remainder of that same day cannot serve as the clean day required afterward.

“Watching” means establishing that no further bleeding occurred. It does not require remaining awake all night; checking the following morning for signs of bleeding is sufficient for the nighttime observation described here.

Under the framework being described, she immerses during the daytime of the clean day but must wait until evening before resuming marital relations. Bleeding later that day could invalidate the clean day and the immersion retroactively, as explained in Halachos 13–14. Immersion in the morning therefore does not make marital relations immediately permissible.

The second day begins with the night following the first bleeding day. If she bleeds that night, the second day cannot serve as her clean day. If the night passes without bleeding and she immerses the following morning, bleeding later that daytime likewise invalidates the day and her earlier immersion.

She has now experienced bleeding on two consecutive days of zivah. She remains a minor zavah, and the next day can serve as the required clean day if no further bleeding occurs.

She does not need two clean days to match the two bleeding days. For a minor zavah, one clean day ordinarily suffices after either one or two consecutive bleeding days. If bleeding occurs on a third consecutive day within the days of zivah, however, she becomes a major zavah, whose requirements are explained next.

This continues the preceding case: she has now experienced bleeding on three consecutive days within the days of zivah. She therefore becomes a zavah gedolah, a major zavah. One clean day no longer suffices; after the bleeding stops, she must count seven consecutive days free of qualifying uterine bleeding.

Under the framework described here, immersion takes place during the seventh clean day. Marital relations remain forbidden until that day ends, because further bleeding before its completion would invalidate the count, as explained below.

This daytime immersion rule concerns a woman whose status as a zavah is established. Halachah 23 gives a different immersion time when her status is doubtful. Present practice likewise requires immersion at night, as explained later in Chapter 11.

The eighth day follows the seven clean days. As explained in Halachah 8, the offering is a further purification requirement and does not delay permission for marital relations.

The “observation day” is the clean day a minor zavah must observe after her bleeding. A major zavah’s corresponding final day is the seventh clean day. In the ordinary cases discussed here, daytime immersion remains subject to the day ending without further bleeding.

The night mentioned here comes before the daytime when immersion is prescribed. For a minor zavah, it begins her observation day. For a major zavah, it begins the seventh clean day, after only six clean days have been completed.

These immersions occur too early and do not remove her existing impurity. The comparison to a niddah concerns this ineffectiveness: just as immersion during her seven-day period cannot end her impurity, immersion at the premature nighttime described here cannot purify a zavah.

Kareis is the severe punishment imposed by Heaven for certain deliberate transgressions. Here, unlike the premature nighttime immersion in the preceding halachah, she immersed at a time when immersion can be effective.

Her immersion is effective provided that the remainder of the required clean day passes without bleeding. Until evening, her purification remains subject to that condition. Exemption from kareis therefore does not mean that relations before evening are permitted.

If bleeding subsequently invalidates her purification, the earlier relations are not treated as a deliberate violation carrying kareis. Halachah 14 explains the resulting obligation to bring a sin-offering.

The criticism concerns proceeding with relations before the day’s outcome is known. Bleeding later that same day can invalidate her purification retroactively. Both the consequences of relations and the status of objects she touches therefore depend on what happens before the day ends.

If the day remains free of bleeding, her purification is confirmed. Objects she touched after immersion are not rendered impure through the zivah impurity discussed here, and relations after immersion do not create the sacrificial liability described below.

“No liability” does not mean that proceeding before evening was permitted. It describes the outcome once the day has ended without further bleeding.

The later bleeding invalidates the clean day and reveals that the immersion did not complete her purification. Its consequences therefore reach back to the period after immersion. Objects she touched become impure where the applicable laws of susceptibility and transmission of impurity are met.

Each member of the couple must bring a sin-offering for the inadvertent violation. These sin-offerings are separate from the offering a major zavah brings as part of her purification. Although the couple were required to wait until evening, the later bleeding establishes retroactively that their relations occurred while she remained impure.

Waiting until evening resolves the uncertainty about that day. If no further bleeding occurs, the required clean period has been completed; if bleeding does occur, she knows that purification has not been achieved.

This halachah concerns a major zavah, who must complete seven consecutive clean days. Bleeding on the seventh day cancels the entire count, even if it occurs shortly before sunset. She cannot preserve the earlier six days and simply replace the seventh.

The day on which bleeding occurs cannot count toward the new sequence. After the bleeding has ceased, she must count seven consecutive clean days anew.

This refers to semen retained after relations and subsequently expelled during her clean-day count, while it still has the halachic capacity to convey impurity.

The earlier clean days remain valid, but the day of the qualifying discharge does not count. She must add a clean day to complete the required total rather than restart all seven. This differs from qualifying uterine bleeding, which cancels the entire count.

A zav is a man with a particular type of discharge that creates ritual impurity. If he experiences a seminal emission during his purification count, he likewise loses one day rather than the entire count.

There are only eleven days in the zivah interval. “The twelfth day” therefore means the day immediately following that interval—the first day of the next niddah period in the reckoning.

Only the first two bleeding days in this case belong to zivah. The third belongs to niddah and cannot join them to establish major-zavah status. The physical continuity of the bleeding does not erase the legal boundary between the periods.

Bleeding immediately after the seven days of niddah is not treated merely as an extension of that period. Days eight, nine, and ten are the first three days of zivah. Bleeding on all three therefore establishes major-zavah status, even if the bleeding began earlier and continued without interruption.

This case concerns a minor zavah whose bleeding occurred on the final day of the zivah interval. She immersed that night without first observing the required clean day. The immersion and relations described here are not permitted conduct.

“Lying and sitting” refers to ritual impurity affecting eligible beds, seats, and similar supporting objects. The woman and the man who had relations with her each have the applicable impurity described here; their detailed rules of transmission are not necessarily identical.

The next day belongs to niddah, so bleeding then cannot join the preceding day’s zivah bleeding. This boundary gives the nighttime immersion a limited effect: despite the impurity that remains, the relations do not incur kareis or the corresponding sin-offering liability. It does not make the relations permissible.

This continues the case of bleeding on the eleventh and final day of zivah. She now immerses at the prescribed daytime rather than during the preceding night. Nevertheless, the requirement to wait until evening remains in place.

They do not incur kareis or a sin-offering obligation for these relations. Nevertheless, having relations before evening violates the requirement to wait.

Unlike bleeding during an ordinary observation day within the zivah interval, bleeding on this day does not retroactively invalidate her purification from the preceding zivah in a way that creates liability for the earlier relations. It belongs to a new category: niddah.

“This has no effect” concerns the earlier relations. It does not mean that the new bleeding is harmless or that she remains permitted afterward. The new bleeding establishes niddah impurity and its associated restrictions.

Bein hashemashos is the twilight period whose classification as day or night is uncertain. Here, that uncertainty falls exactly at the boundary between niddah and zivah.

If the first bleeding belongs to the seventh day, it is niddah blood, and the later bleeding on days nine and ten establishes only minor-zavah status. If the first bleeding belongs to the night beginning day eight, she has bled on days eight, nine, and ten—the first three consecutive days of zivah. She is therefore certainly a minor zavah and doubtfully a major zavah.

Here the uncertainty falls at the opposite boundary. If the twilight bleeding belongs to day eleven of zivah, there are three consecutive zivah bleeding days: nine, ten, and eleven. If it belongs to the following night, it is niddah blood and cannot complete that sequence.

In both cases, the possibility of major-zavah status requires seven clean days. The rules governing immersion and the offering in a doubtful case are explained in Halachah 23.

Once an examination establishes that the bleeding stopped, later bleeding does not make us assume that she had been bleeding throughout the intervening days. We therefore do not use that later discovery to establish an earlier sequence of three zivah bleeding days.

The presumption concerns the absence of renewed bleeding. It does not mean that the examination itself ended her existing niddah impurity or replaced the required immersion. The Maggid Mishneh explains that this presumption applies whether or not she immersed.

Here, no examination established cessation by the transition from the niddah period into the zivah period. Finding no blood later tells us that the bleeding has now ceased, but not when it ceased. It may have continued through three consecutive days of zivah, making her doubtfully a major zavah.

This ruling concerns an interval long enough for the possible three-day sequence to have occurred. The reference to twilight should not be read as an instruction to postpone an examination until then. A hefsek taharah—the examination establishing that bleeding has ceased—is performed before sunset.

When bleeding was found at both ends of the relevant interval, and no intervening examination established that it ceased, the law presumes continuity. She is therefore treated as a definite major zavah, rather than merely a doubtful one.

For the presumption discussed here, a blood-free examination on the first day does not establish the same lasting cessation as an examination from the second day onward. The initial flow is presumed likely to continue during that first day. This explains why the opening ruling specifically recognizes an examination on the second day.

This concerns a major zavah counting seven clean days after the bleeding has been established to have stopped. The examination establishing cessation before the count is called a hefsek taharah.

Her examinations on the first and seventh days establish blood-free findings at both ends of the count. In the absence of an intervening sighting of blood, she is presumed to have remained free of bleeding during the days between them. Those days therefore count even though she did not examine herself on each one.

This ruling addresses examinations that were omitted. It does not prescribe checking only twice during the entire count. At the outset, the Shulchan Aruch directs a woman to examine herself twice on each of the seven clean days.

Here, the later examination took place on the eighth day rather than the seventh. According to the Rambam, that delay does not invalidate the seven-day count. With blood-free findings on the first and eighth days and no known bleeding between them, she is presumed to have remained free of bleeding throughout the intervening period.

The eighth-day examination confirms the presumed continuity of the preceding clean days. It does not create an eight-day counting requirement; the required count remains seven clean days.

In this case, the examination establishing that the bleeding stopped occurred on the third bleeding day, before the clean-day count began. Although she omitted the examination on the first clean day, the Rambam accepts the established cessation together with the blood-free examination on the seventh day. With no known intervening bleeding, the seven days count.

These are the Rambam’s rulings concerning omitted examinations. The differing requirements recorded by other authorities are discussed below.