It is any woman who is old enough that people call her: Mother [Imma], Mother, and she is not embarrassed. Rabbi Zeira and Rabbi Shmuel bar Rav Yitzḥak disagree with regard to this matter. One says that the definition is any woman who does not take offense about being called: Mother, Mother. And the other one says that it is any woman who is not embarrassed by this. The Gemara asks: What is the difference between their definitions? The Gemara answers: The practical difference between them is in a case where a woman is embarrassed but she does not take offense when called: Mother.

The Gemara asks: And how long is a typical menstrual cycle? Reish Lakish says in the name of Rabbi Yehuda Nesia: The average menstrual cycle is thirty days long. And Rava says that Rav Ḥisda says: It is twenty days. The Gemara notes: And they do not disagree. One Sage, Rav Yehuda Nesia, counts all the days of her cycle, including the days of impurity and days of purity. And the other Sage, Rav Ḥisda, does not count the days of impurity, i.e., the seven days of impurity of a menstruating woman and the three days of the sighting of ziva.

§ The Sages taught in a baraita: With regard to an elderly woman for whom three typical menstrual cycles of thirty days passed and then she saw a discharge of menstrual blood, her time is sufficient. And if a further three typical menstrual cycles of thirty days passed for her and she subsequently saw a discharge of menstrual blood, her time is sufficient. And if yet a further three typical menstrual cycles of thirty days passed for her and then she saw a discharge of menstrual blood, after this third time she is now like all normal women, and she transmits impurity retroactively for a twenty-four-hour period or from examination to examination.

The baraita continues: And it is not necessary to teach this halakha in a case where she experienced the three sightings in even intervals of ninety days, as in such a case it is obvious that she assumes the status of a normal woman who transmits impurity retroactively. Rather, even if she had intervals where she decreased, i.e., experienced bleeding at intervals smaller than that, or even if she increased and experienced bleeding at greater intervals, she still assumes the status of a woman who transmits impurity retroactively.

The Gemara infers: The wording of the baraita: Even if she had intervals where she decreased, indicates that it is not necessary to teach the halakha in the case of a woman who experienced bleeding at even intervals. This is puzzling, as on the contrary, if she experienced bleeding at even intervals she thereby fixes her menstrual cycle as being every thirty days, and according to Rabbi Dosa (4b) the halakha is that her time is sufficient.

And if you would say that this is in accordance with the opinion of the Rabbis, who disagree with Rabbi Dosa, as they say that a woman who has a fixed menstrual cycle transmits impurity retroactively for a twenty-four-hour period, then the baraita should have been written in the opposite fashion: Let it say: And the halakha that an elderly woman who sees menstrual blood at intervals returns to the status of normal women and transmits impurity retroactively applies not only to a case where she had intervals where she decreased or increased, i.e., she experienced bleeding less or more than ninety days apart, but this halakha applies even if she experienced bleeding at even intervals.

The Gemara answers: Teach in the baraita in accordance with this altered version: And the halakha applies not only to a case where she had intervals where she decreased or increased, but this is the halakha even if she experienced bleeding at even intervals. And if you wish say instead that this is what the baraita is saying: The halakha that an elderly woman is retroactively impure does not apply to a case when she saw menstrual blood at even intervals. Rather, it applies only if she decreased or increased, i.e., she experienced bleeding at intervals less or more than ninety days apart. But if she saw blood at even intervals, she thereby fixes a set menstrual cycle of ninety days and her time is sufficient. The Gemara adds: And if so, in accordance with whose opinion is this baraita? It is in accordance with the opinion of Rabbi Dosa.

§ The mishna teaches that Rabbi Eliezer says: With regard to any woman for whom three typical menstrual cycles passed during which she saw no menstrual blood, if she experiences bleeding, her time is sufficient. Rabbi Yosei says: In the case of a pregnant woman and a nursing woman for whom three menstrual cycles passed during which they saw no menstrual blood, if she then saw blood her time is sufficient. Rabbi Eliezer cites a proof for his opinion. It is taught in a baraita: There was an incident involving a certain girl in the village of Hitlo who stopped menstruating for three typical menstrual cycles, after which she experienced menstruation. And the matter came before the Sages, and they said that her time is sufficient and she does not transmit impurity retroactively.

The other Sages said to Rabbi Eliezer: Decisions rendered in exigent circumstances are no proof. The Gemara asks: What were the exigent circumstances? Some say that it was during the years of famine, and some say that the girl had handled many ritually pure items and the Sages were concerned for the loss of those pure items if they were ruled retroactively impure.

The Sages taught in a baraita: There was an incident in which Rabbi Yehuda HaNasi acted by ruling that the halakha is in accordance with the opinion of Rabbi Eliezer. After he remembered that Rabbi Eliezer’s colleagues disagree with him on this matter and that he had apparently ruled incorrectly, he nevertheless said: Rabbi Eliezer is worthy to rely upon in exigent circumstances. The Gemara asks: What is the meaning of: After he remembered? If we say that this means after he remembered that the halakha is not in accordance with the opinion of Rabbi Eliezer, but in accordance with the opinion of the Rabbis, if so, how could he act in accordance with Rabbi Eliezer even in exigent circumstances, since the halakha has been decided against him?

Rather, one must say that the halakha had not been stated on this matter, neither in accordance with the opinion of this Sage, Rabbi Eliezer, nor in accordance with the opinion of that Sage, the Rabbis. And what is the meaning of: After he remembered? After Rabbi Yehuda HaNasi remembered that it was not a lone authority who disagrees with Rabbi Eliezer, but it was several Sages who disagreed with him, and there is a principle that the halakha is in accordance with the opinion of the many over the opinion of an individual, he nevertheless said: Rabbi Eliezer is worthy to rely upon in exigent circumstances.

The Gemara continues the discussion of a woman who fails to experience menstruation for three typical menstrual cycles. The Sages taught in a baraita: With regard to a young girl, less than twelve years old, whose time to see the flow of menstrual blood has not arrived and she saw menstrual blood, after the first time her time is sufficient. After the second time, again her time is sufficient. After the third time, she is like all normal adult women, and therefore she transmits impurity retroactively for a twenty-four-hour period or from examination to examination.

The baraita continues: If she then passed three expected menstrual cycles without experiencing bleeding, and then she saw menstrual blood, she returns to the status of a young girl and her time is sufficient. And if it further happens that she again passed three expected menstrual cycles without experiencing bleeding, and then she saw menstrual blood, her time is sufficient. And if she passed three further cycles without experiencing bleeding, and she subsequently saw menstrual blood, she is like all normal adult women. She is considered a woman who experiences regular menstruation at long intervals with breaks of ninety days. And therefore she transmits impurity retroactively for a twenty-four-hour period or from examination to examination.

The baraita concludes: And with regard to a girl whose time to see the flow of menstrual blood has arrived, i.e., she has reached the age of twelve, when she sees menstrual blood for the first time, her time is sufficient. After the second time, she transmits impurity retroactively for a twenty-four-hour period or from examination to examination. If three menstrual cycles then passed without her experiencing bleeding, and afterward she saw menstrual blood, her time is sufficient. This is in accordance with the opinion of Rabbi Eliezer, who holds that any woman who passed three expected menstrual cycles without experiencing bleeding is presumed not to be menstruating.

The Master said in the baraita: If the young girl who had started menstruating passed three expected menstrual cycles without experiencing bleeding and then saw menstrual blood, she returns to the status of a young girl and her time is sufficient.