Some women are aware that they are ovulating because they experience the so-called Mittelshmerz. Most women, however, can detect ovulation only through the use of ovulation kits which did not exist in the times of Chazal. Chazal fixed the rules concerning the Veses (when a man is required to seperate from his wife because of a concern that her menses may begin) based on signs that are easily detectable, i.e. the onset of the menses. Besides the fact that their method is statistacally quite accurate, we are not in a position to change these rules or any other Rabbinic rulings either to be more lenient or even, as in this case, to be more stringent. (See the Rambam, introduction to the Yad ha'Chazakah, where he says that with the closing of the Talmud no new rules may be made that are binding on all Jews for all time.)

b'Chavod,

Yonason Sigler

This is not a Psak Halachah

Thank you for the reference to the Sefer Kenei Bosem of Rav Meir Bransdorfer. I looked it up, and saw that Rav Bransdorfer is not addressing the question of whether women in general are obligated to determine when they are ovulating so that they can keep a Veses twelve or thirteen days later. He is not even addressing the question of whether a woman, who is accustomed to determining the time of her ovulation and knows how many days later her menses will start, is obligated -- in any particular cycle -- to determine when her ovulation will be and then keep the appropriate Veses. He is dealing only with the question of a woman who already knows when she ovulated and knows, based on that, when her menses will start: is she obligated to treat her ovulation in the same way as any Veses based on Simanim. Even there it is not clear to him that it is considered a Veses l'Simanim, albeit his final Psak is to be Machmir.

Gemar Chasimah Tovah,

Yonasan

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