A first approach to Siman 189: the 34 seifim of the Mehaber and the glosses of the Rama, the vocalized Hebrew text with a fluent English translation. How does a woman determine her period (veset)? The benchmark day of the onah beinonit (30 days), the establishment of a period by three times, the period based on the interval (haflagah) and the shift (dilug), the periods of the days of the month and week, the uprooting of a period (akirat veset), the bodily periods (וסתות הגוף), and the case of the minor, the elderly, the pregnant and the nursing woman.
Topic: The menstrual periods — fixed and non-fixed cycles, onah beinonit, haflagah, dilug, uprooting a veset Source: שולחן ערוך יורה דעה סימן קפ״ט
Compiled by: הרב יוסף חיים סממה DAAT · daattorah.com
📑 Study plan
1.The Mehaber's text: the 34 seifim, grouped into 8 thematic families
2.Context: why this siman follows the laws of niddah
4.How a period is set and uprooted: the table of the three times
5.The Taz and the Shach: who they are, a few key entries
6.The gloss of the Rama (הגה): veset from oness and foods
7.Mesuleket damim: the minor, the elderly, the pregnant and the nursing woman
8.Modern practical cases: tracking the veset, the onah beinonit, the symptoms, pregnancy
9.Summary and comprehension questions
1. The Mehaber's text — the 34 seifim in 8 families
Siman 189 is one of the longest and most technical of all of Yoreh De'ah: 34 seifim devoted to the וְסָתוֹת — a woman's menstrual periods and how to anticipate them. After Siman 184 (the mitzvah of פרישה, separating as the period approaches), the Mehaber (Rabbi Yosef Karo) here details how a period is calculated, established and uprooted. The Rama (Rabbi Moshe Isserles) adds his glosses (הגה). Given the number of seifim, we present them grouped into eight families that cover the whole content, citing for each the representative vocalized Hebrew text.
Family 1 — Onah beinonit and the fixed veset: the foundation (seifim 1, 4)
Seif 1 — Without a fixed period: the 30th day (onah beinonit)
Every woman who has no fixed period (veset kavua) must be concerned for the 30th day counting from her last sighting, for this is the onah beinonit (the "middle period") for women in general (li-stam nashim). And if she has a fixed period at a known interval — every 20 days, or every 25 — she is concerned for that known time.
Seif 4 — The practical difference between fixed and non-fixed
There is a further difference between a period established three times and one that is not: for a fixed period, even if the time (onah) has passed without her feeling anything, she remains forbidden to her husband until she examines herself (tivdok) and finds herself pure. For a non-fixed period, if the time passed without her examining or seeing, she is permitted, since the time has passed. And the onah beinonit of the 30th day has the status of a fixed period (dinah ke-veset kavua).
The central idea: every woman is "concerned" (choshéshet) for a day on which her period might return, and must abstain then. Without a regular cycle, that benchmark day is the onah beinonit, the 30th day. With a regular cycle, it is the known day. The decisive distinction (seif 4): a fixed period requires a bedikah (examination) even if nothing was felt; a non-fixed period, passed without seeing anything, lifts on its own — except the onah beinonit, which carries the stringency of a fixed period.
Family 2 — How a period is established: the three times (seifim 2-3)
Seif 2 — Three equal intervals; four sightings for the veset ha-haflagot
How is a period established? When the woman sees four times with, between those sightings, three equal intervals: for example she sees today, then after 20 days another time, again after 20, again after 20 — this is called the veset ha-haflagot (the period of the interval). It requires four sightings, because the first does not count in the reckoning, since it is not itself an interval (haflagah).
Seif 3 — The period set by hours (veset li-sha'ot)
If she set a period by hours and not by days, she is concerned only for her precise hour. And that period is uprooted in a single hour (passed without her seeing), even without a bedikah.
The principle of establishment: a period becomes "fixed" only after three identical intervals. For a period based on the interval (ha-haflagot), four sightings are needed — because the first bleeding does not yet establish an interval; it is the three following intervals that must be equal. Once fixed, the period is uprooted only after three intervals passing empty (see Family 5).
Family 3 — Veset ha-haflagot and the dilug (seif 5)
At times the interval by which a period is established advances by shift (dilug): for example she sees today, a second time after 30 days, a third after 31, a fourth after 32 — she has established a period by the shift of intervals. Whether the shift is large or only one single day, as long as it is regular (mashveh re'iyatah), she has established a period.
Dilug = a regular shift. A period can be established not on a constant interval, but on an interval that lengthens regularly (30, 31, 32…). What matters is the regularity of the progression, even by a single day. This is the veset ha-haflagot in its subtlest form.
Family 4 — Days of the month and week: dilug, sirug, day and night (seifim 6-13)
Just as a woman establishes a period by the interval (of equal or unequal days), she also establishes it by the days of the month and the days of the week, equal or unequal. How? If she sees three times on Sunday (echad ba-shabbat), or Thursday, or on the 1st of Nissan, the 1st of Iyar and the 1st of Sivan — she has established a period on that day.
Seif 13 — Always within the same onah: day or night
A woman does not establish a period — even if she has seen three Rosh Chodesh in a row — unless all those sightings are within a single onah: by day or by night. And if she saw three times by day and the fourth by night (or the reverse), she is concerned for both day and night.
This family lays out the whole combinatorics of dates: by day of the month or week, with its variants — the dilug (shift: the 15th, 16th, 17th of the month, seifim 7-8), the sirug (skipping a month, where, unlike the dilug, the first sighting counts, seif 12), Rosh Chodesh (seif 9), and the day / night rule (seif 13): the onah is always either diurnal or nocturnal, and a mixture obliges her to be concerned for both. If a woman "skips" a month without regularity (sirgah), she does not establish (seifim 10-11).
Family 5 — Uprooting a period: the change, the three times (seifim 14-16)
Seif 15 — A fixed period is uprooted only over three times
If she changed her sightings without making them equal — once on the 30th day, the second on the 32nd, the third on the 34th — the old veset is uprooted, and she has no period at all. But if she returns to seeing on the day of the old period, it resumes its original establishment, and she is always concerned for it until it is uprooted from her three times.
The symmetry of the three times: just as three intervals are needed to establish a period, three intervals passing empty are needed to uproot it (akirat veset). A single ad-hoc change is not enough: the fixed period is tenacious. Seif 14 describes the shift (shinui — when a woman moves from one day to another: both are then to be feared); seif 16 applies the same rule to the Rosh Chodesh veset (three Rosh Chodesh empty to uproot it), and returning to see restores it at once.
Family 6 — The period from oness and the leap (kefitzah) (seifim 17-18)
Seif 17 — A period set by oness alone is not a period
Any period established through a constraint (oness) — for example because she leapt and saw (kaftzah ve-ra'atah) — even if she has seen this way several times, is not a period, because it is on account of the constraint that she saw. Gloss of the Rama: nevertheless she is concerned for it like a non-fixed period. But if she leapt and saw, leapt and saw, leapt and saw — she has established a period (to the leap itself).
The role of constraint: a bleeding caused by a physical effort (a leap, a fall…) is not "natural." A period that forms only through that constraint does not become a true fixed period — yet one is concerned for it as for a non-fixed one. By contrast, if the sequence leap + sighting repeats three times, it is the leap itself that becomes the period (seif 18: a leap on a fixed date — three Rosh Chodesh or three Sundays — establishes a period for the leap of that day).
Family 7 — The bodily periods (וסתות הגוף) (seifim 19-26)
Seif 19 — Yawns, sneezes, pains: a period set by a symptom
A woman may establish a period by phenomena that occur in her body: for example she yawns (mefahéket) — like someone stretching the arms from weariness, or opening the mouth from fatigue — or she sneezes (mit'atéshet), or feels a pain in the lower abdomen (pi keresah u-shifulei me'eha), or is seized by feverish shivers (tzirei ha-kadachat), or feels her head and limbs heavy. Each of these signs may become the herald of her period.
Seif 23 (gloss) — Eating garlic, onion, pepper (the Rama)
All these periods established by a phenomenon do not combine with one another: only one same sign repeated three times (for example yawning three times and seeing) establishes a period. Gloss of the Rama: if she ate garlic and saw, ate onion and saw, ate pepper and saw — some say she has established a period of seeing upon every consumption of pungent foods (devarim charifim).
Veset haguf: the period tied to the body. The mechanism is the same as for dates (three times to establish, once to be concerned, once to uproot), but the marker is a physical symptom rather than a date. Two subtleties: one must isolate the cause — if the symptom and the date dissociate, הוברר הדבר ("the matter has become clarified") reveals which of the two is determinative (seif 20); and each symptom is established separately, without combining with another (seif 23). One is concerned from a single occurrence (seif 26), and the period likewise lifts in one.
Family 8 — Minor, elderly, pregnant, nursing and veset within a veset (seifim 27-34)
Seif 28 — The elderly woman: three intervals empty = mesuleket damim
An elderly woman (zekenah) over whom three intervals have passed since she aged without her seeing is called mesuleket damim ("removed from bloods"): she is no longer concerned for her old period. Gloss of the Rama: the minor (ketanah) and the elderly woman are also not concerned for a non-fixed period.
Seif 34 — Pregnant and nursing: suspension then resumption of the period
A pregnant woman, once her pregnancy is recognized (mi-she-hukar ubarah), and a nursing woman, throughout the 24 months (kaf-dalet chodesh) after the birth, are no longer concerned for the old period: even if she had a fixed period whose time falls within this span, she needs no bedikah and remains permitted to her husband — for they are mesuleket damim. But once the days of pregnancy and nursing have passed, they return to being concerned for the old period.
Mesuleket damim = "removed from bloods." Four categories of women lie outside the ordinary regime of vesatot: the ketanah (the girl before age — who may nonetheless establish a period, with nuances, seif 27); the zekenah (elderly woman — three intervals empty render her mesuleket damim, seifim 28-31); the me'uberet (pregnant, once the fetus is recognized) and the menikah (nursing, 24 months) — who do not establish a period and are not concerned for the old one (seifim 33-34), then return to it. Seif 32 adds the case of the veset within a veset: two interlocking periods (e.g. Rosh Chodesh, and the 2nd of the month) established together.
2. Context — where this siman fits
Siman 184 set the mitzvah of פרישה: separating as the period approaches (the eve of the expected time). But to know when to separate, one must first be able to anticipate the period. That is the whole purpose of Siman 189: it provides the calculation that determines the day to be concerned for (yom ha-veset). The central question is no longer "how does one become pure?" but "which day must be feared, and with what stringency — a mere precaution or a real bedikah?"
The major questions of the siman
Question
Where?
Typical answer
Which day to fear without a fixed cycle?
Seifim 1, 4
The onah beinonit: the 30th day (stringency of a fixed period)
How a period is established?
Seifim 2-3
Three equal intervals (four sightings for the interval)
The interval and the shift
Seif 5
Constant haflagah, or regular dilug (30, 31, 32…)
The days of the month / week
Seifim 6-13
Fixed date, dilug, sirug, Rosh Chodesh; always day or night
Uprooting a period
Seifim 14-16
Three intervals empty; the return restores it
Oness, kefitzah and bodily symptoms
Seifim 17-26
Oness alone ≠ period; veset haguf set in three times
Minor, elderly, pregnant / nursing
Seifim 27-34
Mesuleket damim: suspension then resumption
The cross-cutting idea: everything is a matter of chazakah (presumption) and counting. How many times has the period appeared at the same rhythm? Three times → it is fixed and requires a bedikah. Three intervals empty → it is uprooted. The calculation can be highly complex (interval, shift, leap, crossed symptoms) — which is why, in practice, one must consult a Rav.
3. The key concepts of this siman
To understand Siman 189, one must master a technical vocabulary describing how a period is identified, established, shifted and uprooted.
וֶסֶת (veset) — The period: the time at which a woman is accustomed to see her blood. The whole siman aims to anticipate it in order to apply the perishah (Siman 184). One distinguishes the fixed veset (established by three times) from the non-fixed veset.
עוֹנָה בֵּינוֹנִית (onah beinonit) — The middle period: the 30th day counting from the last sighting. It is the default benchmark day for any woman without a fixed cycle (seif 1); it has the status of a fixed period (seif 4) — she examines herself even if nothing was felt.
חוֹשֶׁשֶׁת (choshéshet) — "She is concerned": taking into account a day on which the period might return, and so abstaining from it. A fixed veset further requires a bedikah; a non-fixed one, passed without seeing, lifts on its own.
הַפְלָגָה (haflagah) — The interval: the period based on the number of days elapsed between two sightings. It requires four sightings (three equal intervals), since the first sighting does not yet establish an interval (seif 2).
דִּלּוּג (dilug) — The shift: a period in which the interval (or the day of the month) advances regularly — 30, 31, 32… or the 15th, 16th, 17th of the month. It is the regularity of the progression that establishes the period (seifim 5, 7-8).
סֵירוּג (sirug) — The skip: seeing every other month (from Rosh Chodesh to non-consecutive Rosh Chodesh). Unlike the dilug, here the first sighting counts in the reckoning (seif 12).
עֲקִירַת וֶסֶת (akirat veset) — The uprooting: a fixed period disappears only after three intervals passing without seeing. Returning to see on the old day restores it at once (seifim 14-16).
וֶסֶת הַגּוּף (veset haguf) — The bodily period: established not by a date but by a physical symptom (yawn, sneeze, pain, pungent food). The same counting rules apply, but one is concerned from a single occurrence (seifim 19-26).
מְסֻלֶּקֶת דָּמִים (mesuleket damim) — "Removed from bloods": the status of the minor, the elderly, the pregnant and the nursing woman, who fall outside the ordinary regime of vesatot — they do not establish a period and are not concerned for the old one (seifim 28, 33-34).
The common thread: the number three (the chazakah) governs everywhere. Three identical intervals establish; three intervals empty uproot. The major exception is the onah beinonit — a single benchmark day (the 30th) that is not "established" by repetition but imposes itself on every woman without a regular cycle.
4. Establish and uproot — the table of the three times
The whole mechanism of the siman lies in the symmetry of the number three. We cross which type of period? with how many times are needed to establish / uproot it?
Type of period
To establish
To uproot
Day of the month / week (fixed date)
3 sightings on the same date
3 intervals empty
Veset ha-haflagot (interval)
4 sightings (3 equal intervals)
3 intervals empty
Dilug (regular shift)
4 sightings shifted regularly
3 intervals empty
Veset haguf (symptom)
3 times the same symptom + sighting
1 time empty (lifts quickly)
Onah beinonit (30th day)
Imposed by default (no fixed cycle)
Status of a fixed period
The logic in one sentence: three identical intervals create a presumption (chazakah) that the woman sees at that rhythm → the period is fixed and requires a bedikah. Three intervals empty break that presumption → the period is uprooted. The interval (haflagah) requires one extra sighting, since the first sighting does not yet establish a gap.
The practical point: one is concerned from the very first time (choshéshet be-pa'am achat) for a day on which the period already appeared, even before it is "fixed"; and a non-fixed veset lifts in one empty occurrence. The complexity — especially for the dilug, the sirug and crossed symptoms — requires consulting a Rav.
5. The Taz and the Shach — the great commentators
In Yoreh De'ah, the Shulchan Aruch is never read alone. Two great commentaries accompany it and structure practical study: the Taz and the Shach. On the vesatot, the Taz is particularly extensive (some fifty notes for this siman alone). To these one adds the great Acharonim of niddah: the Sidrei Tahara and the Chochmat Adam / Binat Adam.
The Taz (ט״ז) — abbreviation of טורי זהב, Turei Zahav, by Rabbi David haLevi Segal (Poland, 17th century). On Siman 189 he expands at length on the combinatorics of establishment (interval, dilug, sirug), the uprooting, the veset haguf, the veset from oness and the case of the pregnant / nursing woman.
The Shach (ש״ך) — abbreviation of שפתי כהן, Siftei Kohen, by Rabbi Shabtai haCohen (Lithuania, 17th century). The reference commentary on Yoreh De'ah, of great analytical depth.
A key entry: why four sightings for the interval?
The question recurs constantly: why does the veset ha-haflagot require four sightings while the veset of the days of the month requires only three? The answer of seif 2, taken up at length by the Taz, is simple and profound: an interval exists only between two sightings. The first sighting is merely a starting point — it establishes no gap. One therefore needs a first sighting, then three equal intervals, that is four sightings in all. For a date of the month, by contrast, the first sighting is already "the 1st of Nissan" — a marker in itself.
Isolating the cause: huvrar ha-davar
The Taz and the Shach stress, regarding the veset haguf, the principle הוברר הדבר ("the matter has become clarified") of seif 20: when a symptom (the yawn) and a date (Rosh Chodesh) coincide, how does one know which of the two heralds the period? One dissociates them: if she yawns on another day and sees, it is the yawn that counts; if she sees on Rosh Chodesh without yawning, it is the date. Practice therefore demands careful observation — another reason to keep precise records and consult a Rav.
6. The gloss of the Rama (הגה)
The Rama (Rabbi Moshe Isserles) adds to the Mehaber's text glosses reflecting Ashkenazi practice. Here are his most notable interventions in this siman.
On seif 17 — the period from oness
Gloss of the Rama: ומכל מקום חוששת לו כמו לוסת שאינו קבוע — "nevertheless she is concerned for it like a non-fixed period." The Mehaber states that a period established by constraint alone is not a true period; the Rama clarifies that it is not thereby ignored: one is concerned for it at least as for a non-fixed period.
On seif 23 — the pungent foods
Gloss of the Rama: אכלה שום וראתה… יש אומרים שקבעה לה וסת לראות על ידי כל אכילת דברים חריפים — "if she ate garlic and saw… some say she has established a period of seeing through every consumption of pungent foods." The Rama thus broadens the notion of veset haguf to dietary causes (garlic, onion, pepper) that regularly bring on the sighting.
On seif 28 — minor and elderly
Gloss of the Rama (in the name of the Rashba): וקטנה וזקנה אינן חוששות לוסת שאינו קבוע — "the minor girl and the elderly woman are not concerned for a non-fixed period." The Rama thereby lightens the regime for these two categories, whose cycle is not (or no longer) regular.
The Rama carefully distinguishes the baseline law (the Mehaber) from Ashkenazi practice: he tightens in places (one is concerned even for the oness-period as a non-fixed one; he adds the pungent foods) and lightens elsewhere (minor and elderly exempt from the non-fixed). In every case, these nuances confirm that a real case is not decided alone.
Seifim 27-34 step outside the ordinary regime: they deal with women whose cycle is suspended. The central concept is מְסֻלֶּקֶת דָּמִים — "removed from bloods."
The ketanah (girl before age): she may establish a period like other women (3 sightings, 4 for the interval), with nuances; and she is not concerned for a non-fixed period (seif 27).
The zekenah (elderly woman): three intervals passing without seeing render her mesuleket damim; if she returns to seeing, her status becomes that of a young girl again (seifim 28-31).
The me'uberet (pregnant, once the fetus is recognized) and the menikah (nursing, 24 months): they do not establish a period and are not concerned for the old one, even a fixed one — mesuleket damim (seifim 33-34).
Category
Status
Resumption
Ketanah
May establish (nuances); no non-fixed
—
Zekenah
Mesuleket damim after 3 intervals empty
Returns to seeing → status of a tinoket
Me'uberet (fetus recognized)
Mesuleket damim; no bedikah
After the birth
Menikah (24 months)
Mesuleket damim; no bedikah
After 24 months → returns to the old one
And seif 32 adds the particular case of the veset within a veset: a woman may establish two interlocking periods (for example seeing three times on Rosh Chodesh, and the next time on the 2nd of the month as well as Rosh Chodesh…) — she then has two periods to be concerned for. The transition out of one of these statuses (zekenah, pregnancy, end of nursing) is precisely the kind of situation in which one consults the Rav.
8. Modern practical cases
How do these rules apply today? Here are four common situations illuminated by our siman.
Case 1 — Tracking the veset (calendar, taharat ha-mishpacha app)
To determine whether a period is fixed, or to apply the onah beinonit and compute a haflagah, one must record every sighting (re'iyah) precisely. Many couples today use a dedicated calendar or a taharat ha-mishpacha app. These tools compute the days to be concerned for and the corresponding perishah (the separation on the eve, cf. Siman 184). But no app replaces the analysis of a real case: for the halacha le-ma'aseh, consult your Rav.
Case 2 — The onah beinonit (the 30th day)
For most women who do not have a perfectly regular cycle, the benchmark day is the onah beinonit, the 30th day from the last sighting (seif 1). It carries the stringency of a fixed period: one examines (bedikah) even if nothing was felt (seif 4). The exact computation of the 30th day (from which sighting, by day or by night) is for the Rav.
Case 3 — Physical symptoms (veset haguf)
A woman notices that lower-abdominal pains, headaches or great weariness regularly precede her period. The siman (seifim 19-26) teaches that these signs may constitute a veset haguf that must be feared — from a single occurrence as a precaution, and established over three times. One must still isolate the true cause (huvrar ha-davar). This is delicate: for the halacha le-ma'aseh, consult your Rav.
Case 4 — Pregnancy and nursing
During pregnancy (once the fetus is recognized) and nursing (24 months), the woman is mesuleket damim: she is no longer concerned for her old period, even a fixed one (seifim 33-34). But the transitions — end of pregnancy, postpartum, end of the 24 months — are delicate moments when the regime changes. For these passages, consult your Rav.
The common thread of the four cases: the calculation of the vesatot is one of the most technical domains in all of halacha — intervals, shifts, leaps, symptoms, transitions. Before any conclusion, one records one's sightings precisely; but the concrete decision always belongs to the Rav, who masters the combinatorics and the factual details.
9. Summary of Siman 189
The essence of Siman 189 in a few sentences:
Without a fixed cycle, one is concerned for the onah beinonit — the 30th day; with a fixed cycle, the known day (Family 1).
A period is established over three equal intervals; the veset ha-haflagot requires four sightings (Family 2).
The veset ha-haflagot may advance by a regular dilug — 30, 31, 32… (Family 3).
One also establishes by the days of the month / week, with dilug, sirug and the day / night rule (Family 4).
A fixed period is uprooted only over three intervals empty; the return restores it (Family 5).
A period established by oness alone is not a true period, but one is concerned for it as a non-fixed one (Family 6).
The bodily periods (yawn, sneeze, pains, pungent foods) are established over three times; one is concerned from one (Family 7).
The minor, the elderly, the pregnant and the nursing woman are mesuleket damim; the veset within a veset interlocks two periods (Family 8).
Memory table
Situation
Rule
Woman without a fixed cycle
🟡 Onah beinonit: 30th day (stringency of a fixed period)
Three identical intervals
🟢 Fixed period (4 sightings for the interval)
Three intervals empty
🔴 Period uprooted (the return restores it)
Period set by oness alone
🟡 Not a true period, but feared as non-fixed
Bodily symptom (veset haguf)
🟡 Feared from one occurrence; established over three
Pregnant / nursing
🟢 Mesuleket damim; resumption after pregnancy / the 24 months
Comprehension questions
Check your understanding:
What is the עונה בינונית? Why does it have "the status of a fixed period" (seifim 1, 4)?
What is the practical difference between a fixed veset and a non-fixed one passed without seeing (seif 4)?
How many sightings are needed to establish a וסת ההפלגות? Why one more than for a date (seif 2)?
What is the דילוג? How does it differ from the סירוג (seifim 5, 7-8, 12)?
Why must a period be "wholly within a single עונה" — day or night (seif 13)?
How many intervals empty are needed to uproot a fixed period (seifim 14-16)?
Is a period set by אונס alone a true period? What does the Rama rule (seif 17)?
What is a וסת הגוף? How does one isolate the cause (הוברר הדבר, seifim 19-20)?
Who is מסולקת דמים? What happens to the pregnant / nursing woman after pregnancy / the 24 months (seifim 33-34)?
What is a וסת בתוך וסת (seif 32)?
To go further
If you wish to deepen this siman:
📚 Level 2 — Lamdan: the pilpul — the nature of the "veset concern" (de-oraita or de-rabbanan, link to Siman 184), the logic of the chazakot (three times), the combinatorics of establishment (haflagah / month / week / dilug / sirug, Taz), and veset haguf vs veset of the days
✨ Level 3 — Synthesis: the comparative tables (establish / uproot, types of vesatot, mesuleket damim), the golden rules and rapid memorization of the 34 seifim
⚖️ Level 4 — Daat HaRav (Chabad) & Halacha lema'asse: the Chabad mesorah in the tracking of vesatot and the practical ruling (Beit Yosef, Rama, Shach, Taz, Sidrei Tahara, Chochmat Adam, Aruch haShulchan, Taharat haBayit, Shevet haLevi)
The sources of this level are available on Sefaria: