A woman experiencing uterine blood, not part of normal menstruation, was classified as a zavah in the days of the Temple in Jerusalem and remained in a state of ritual impurity for 7 days before immersion. Today, the law of zavah remains in effect in Orthodox Judaism, in two respects. Due to extreme conditions in Roman Palestine in the time of the Amoraim, women's periods became irregular, and women became unable to determine whether or not their discharges were regular (niddah) or irregular (zavah).