Responsa for Niddah 31:29

אף אנן נמי תנינא דתנן ר"מ אומר

refers to a woman who did not examine herself within the period of the duration of her menstruation.<span class="x" onmousemove="('comment',' But did so later on. As it is quite likely that earlier, during the period of menstruation, there was a discharge, the woman must well be deemed unclean. An old ed. inserts here: 'And there are others who say that one Master spoke of one particular case and the other spoke of another particular case and there is in fact no difference of opinion between them' (v. Maharsha and marginal gloss). ');">²⁷</span>

Teshuvot Maharam