Throughout all of the eleven days of potential zivah that follow the seven days of niddah, a woman is presumed to be pure. Not only she is permitted to her husband, without checks or doubts, but even in the times of the Temple, when those women who handled ritually pure foods, had to check themselves, this requirement was suspended during those eleven days.
However, for a man who had a zivah discharge or for a woman who had the same, this presumption is not true, and they are assumed to be ritually impure, unless they checked themselves to ascertain purity.
Finally, if she did not check herself, she is still presumed to be pure. This last rule seems to imply that checks are needed, whereas the first rule told us that they are not!? – One explanation is that the last rules talks about the first seven days, not eleven days that follow. Talmud gives three more explanations of this difficulty, some of them ascribing this complete ruling to the stringent opinion of Rabbi Meir.
Art: Simone Pignone - A personification of Purity