Veset Haguf (Symptoms of menses)
A woman can anticipate her menses and establish a veset (regular cycle) based on physical symptoms which signal the onset of menstruation. This is called a veset haguf (bodily pattern), and may be established either independently of a veset hayamim (calendar-based pattern) or in combination with one.
The Shulchan Aruch (Code of Jewish Law) lists several possible symptoms, including those commonly cited today as premenstrual symptoms. In order to establish a veset haguf, a woman must experience her menses only in conjunction with these symptoms – either immediately upon the onset of menstrual bleeding or at a fixed interval beforehand.
The rules for establishing a veset haguf are complex. A woman should take note of any premenstrual symptoms and their proximity to the onset of her menses, and consult a rabbi if she notices a pattern.
[For a comparison of symptoms listed in the halachic literature with those listed in the medical literature, see: Ganzel, T. and Zimmerman, D., Veset Haguf: Hebet Refui Hilchati in Techumin 20 5760, published by Machon Tzomet, Gush Etzion, Israel.]