Uprooting a Veset Kavua: Graphic Calendars

A woman establishes a veset kavua (established veset) if her cycle follows a consistent and predictable pattern for three consecutive cycles. If on three consecutive occasions the date of the veset kavua passes with no bleeding, then the veset kavua is "uprooted" and she no longer anticipates it.

The laws of a veset kavua are explained in the article on Veset Kavua. This article presents graphic calendars to illustrate how such a veset is uprooted.

If a woman has established a veset kavua, but one month, her menstruation begins on a different day, she continues to observe her veset kavua the following month .  She also observes yom hachodesh (the day of the Hebrew month) and the haflagah (interval) based on her most recent menses, but she does not observe onah beinonit (the average onah).

For example, a woman has a veset kavua for the 15th day of the month. But her menses begin only on the 18th day of Nissan. In Iyar, she will observe:

1. The 15th of Iyar, which is her veset kavua.
2. The 18th of Iyar, which is the yom hachodesh from her actual menses.
3. The 20th of Iyar. This is a 33-day interval after the 18th of Nissan. The interval between her two previous menstrual periods, on the 15th of Adar and the 18th of Nissan, was 33 days.

Adar

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15     Kavua
16	17	18	19	20	21	22
23	24	25	26	27	29	29

Nissan

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
1	2	3	4	5	6	7
8	9	10	11	12	13	14
15	16	17	18	19	20	21
22	23	24	25	26	27	28
29	30

Iyar

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
		1	2	3	4	5
6	7	8	9	10	11	12
13	14	15	16	17	18	19
20	21	22	23	24	25	26
27	28	29

If on three consecutive occasions the date of the veset kavua passes with no bleeding, then the veset kavua is "uprooted" and she no longer observes it. From that point on, she has a veset she'eino kavua and observes yom hachodesh, the haflagah, and the onah beinonit.