Leviticus 15:22

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.

The idea of normal and abnormal, along with the created order, helps interpret these rules (see “Clean, Unclean, and Holy” Theme Note). Bodily discharges, like infections (see study note on Leviticus 13:1–46), were not considered "normal" because they weakened a person's health. This made the person seem incomplete. Whether male (15:1–18) or female (15:19–33), such a person became unclean.