מתני' שמאי אומר כל הנשים דיין שעתן - אם ראתה דם די לנו אם תטמא תרומה וטהרות שתגע בהן משעת ראייה ואילך ולא אמרי' כי היכי דהשתא אישתכח דם בבית החיצון אי הות בדקה נמי מקמי הכי הוה אישתכח וכותלי בית הרחם העמידוהו וקיימא לן בפ' יוצא דופן (לקמן נדה דף מ.) כל הנשים מטמאות בבית החיצון:

Mishnah: Shammai says, "All women, their time [of seeing blood] is enough" - If she sees blood, it is enough for us if she defiles terumah and taharot that she came in contact with from the time [of seeing blood] and onward, and we do not say that "just as she has now found blood in the outer chamber [of the uterus], if she had performed a bedikah [check] even earlier, she would have found blood as well, and the [only reason she did not see the blood before is because the] walls of her uterus held the blood in." And we have [already] established in the chapter "Yotetzeh Dofen" (Yevamot 40a) that all women become impure [for the laws of Niddah when blood is] in the outer chamber [of the uterus].

מפקידה לפקידה - בדקה עצמה באחד בשבת ומצאתה טהורה וליום רביעי בדקה ומצאתה טמאה חיישינן ומטמאה מספק כל הטהרות שנתעסקה בהן משעת בדיקת אחד בשבת דשמא עם סילוק ידיה ראתה וכותלי בית הרחם העמידוהו:

"From pekidah to pekidah" - [A case of where a woman, for example,] checked (performed a bedikah) herself on Sunday and found that she was ritually pure, and on Wednesday checked (performed a bedikah) and found that she was ritually impure. [In this case] we worry [that she was ritually impure even before she found blood] and declare ritually impure, out of doubt, all taharot that she came into contact with from the time of her bedikah on Sunday. For it is possible that as soon as she took her hand away [from the bedikah on Sunday] she "saw" (i.e. there was a flow of) blood, and the walls of her uterus held the blood in place.

ואפי' לימים הרבה - בין בדיקה ראשונה לשניה מטמאינן כל הטהרות שנתעסקה בהן בינתיים אבל הנך דמקמי בדיקה קמייתא טהורות דהא כשבדקה עצמה מצאתה טהורה:

"And even for many days"...between the first check (bedikah) and the second check (bedikah), we declare all taharot she handled during days in between (the first and second bedikot) to be ritually impure. However, those [taharot that were handled before the first bedikah are] ritually pure, since she checked herself (through a bedikah) and found herself to be ritually pure.