Menstrual Periods

Bukhari :: Book 1 :: Volume 6 :: Hadith 320

Narrated Um Salama:

While I was lying with the Prophet under a woolen sheet, I got my menses. I slipped away and put on the clothes for menses. The Prophet said, "Have you got your menses?" I replied, "Yes." He called me and I slept with him under the woolen sheet.