19“You shall not approach a woman to uncover her nakedness while she is in her menstrual uncleanness.
According to regulations in the Cleanliness Code, a woman in her period of menstruation is ritually unclean (See commentary on Leviticus 12:2). It is clear that anyone who touches her during that time becomes ceremonial unclean as well.
19 “You shall not approach a woman to uncover her nakedness while she is in her menstrual uncleanness.