If her menstrual impurity came to be upon a man lying down with her (as when, unwittingly, a husband had sexual relations with his wife at the beginning of menstruation), he was rendered unclean for seven days, and the bed upon which he might lie down was considered unclean.

If a man and a woman deliberately cohabited during her menstrual impurity, they were cut off in death. (Le 18:19; 20:18) The prohibiting of sexual union during menstruation probably contributed to health, perhaps preventing, for instance, the occurrence of inflammation in the genital area, simple urethritis.