A woman's menstrual period is natural and not a disease. But because it involved a bloody discharge, she became ceremonially unclean (see Leviticus 15:32–33). The rules were similar to those for a man with a bodily discharge (15:2–12). She could stay at home, but anything she sat on became unclean. Anyone who touched her had to wash, and she probably did the same after the seven-day quarantine. There was no animal sacrifice needed.