Explanation #1 (Rashi): This excludes days 10 and 11, which are not proper to begin becoming a Zavah Gedolah.

Explanation #2 (R. Chananel): This excludes days one and two of the 11 [days of Zivah], for she still cannot become a Zavah Gedolah unless she will see on day three.

Question: Even without Nefalim we can find more than 150, e.g. Yehudah and Chizkiyah (the latter twin came out many days after the first), and after the second baby she counts 80 for a female, seven days of Nidah and two days afterwards!

Answer: This is not common.

Question: Even without Koshi, we find that [she sees] all her days and she does not become a Zavah, e.g. she miscarried after 80 for a female, seven days of Nidah and two days after Nidah!

Granted, below, regarding one who sees 100 days, we can say that he discusses one child. Alternatively, he discusses a viable baby;

However, here we discuss Nefalim, since it says "there is no Koshi for Nefalim!"

Answer: We do not discuss Yoledes without Koshi.

Explanation: The Shofar that they blow when they are Mekadesh Rosh Chodesh of the ninth month of her pregnancy [causes that all blood seen afterwards b'Koshi is due to the birth].

Question: How is it proven that the lunar month causes this? Perhaps the ninth month after eight months of 30 days from the start of her pregnancy causes this, even if it begins in the middle of the lunar month!

Answer #1: If so, he should have said "the last month suffices." "Her month" connotes the month that is clarified, i.e. the lunar month;

"We learn from this" applies to the Mishnah just like to the Beraisa. (Both say "her month.")

Answer #2: The Beraisa proves that she can give birth in partial months, like it taught "even if she gave birth at the beginning of month nine"...

And we would not call one day [after eight months of 30 days] "her month." However, regarding lunar months, it is proper to call this "her month", even if it is only one day.

Answer #3: The Seifa of the Beraisa proves that the lunar month causes this, for it says "if she [saw blood amidst] Koshi for one day at the end of the eighth month and two days at the beginning of the ninth month, and even if she gave birth at the end of the ninth month...

How could she know that Koshi was two days in the ninth month, if not that we discuss lunar months?! (Even if she had Bi'ah only once, she cannot know if conception was that day, or a day or two later!)

Granted, when she gave birth at the [very] end of nine months, she could know, i.e. she gave birth 273 days after relations. Then, her ninth month began 30 days before birth;

[It must be that] conception was not until the third day from relations. If it were on the first [or second] day, she would have given birth 271 [or 272] days after relations, for the fetus does not delay in the womb more than this;

We do not hold like Rabah Tosfsah in Yevamos (80b, who says that it can delay 12 months).

In any case, since it says even if she gave birth at the end of nine months, this implies that she can give birth in the middle of the ninth month, and then she cannot know whether she had exactly two days of Koshi in the ninth month;

If she had Koshi on days 240, 241 and 242 from Bi'ah, perhaps conception was not until the day after Bi'ah. If so, only one day of Koshi was in the ninth month!

If she had Koshi on days 241, 242 and 243, if conception was on the day of Bi'ah, three days of Koshi were in the ninth month!

Conclusion: Rather, surely the Shofar causes [that Dam Koshi is due to the birth].

Assertion: According to R. Yehudah, the Shofar of nine months causes this. If she became pregnant at the end of a month, she [can] give birth at the beginning of the ninth month;

If we required the first eight months to be full, when she became pregnant at the end of a month, the Shofar of the ninth month (i.e. after eight full months passed) would be the 10th month, unless she became pregnant at the beginning of the month!

Implied question: Why couldn't we say that R. Yehudah discusses Nefalim?

Answer #1: It is because he mentioned [Koshi in months] eight and nine, and not in three and four.

Answer #2: It is because he said "Yaldah" (gave birth, which connotes a viable baby).

Question: Also without the Kal va'Chomer, why is he Metamei? It should suffice [to be Metaher] because Koshi is no worse than Shofi! Why should she be Teme'ah due to Koshi?

Answer: R. Eliezer's reason is like Rava explains in the Gemara - "Dameha" due to herself, but not due to the fetus;

This is why Rabanan need a Kal va'Chomer, and due to the Kal va'Chomer we should expound the verse "Dameha" for another matter;

They cannot establish the verse even for Yemei Nidah, for which there is no Kal va'Chomer, for Rabanan also expound "Teshev" - one sitting for all of them.

R. Eliezer holds that since we can establish the verse for Yemei Nidah, even if we say the Kal va'Chomer, due to Dayo you should be Metaher only Yemei Zivah, but in Yemei Nidah she is Teme'ah;

According to him, even in Yemei Zivah she is Teme'ah due to "Teshev" - one sitting for all of them, like it says in the Gemara.

Explanation #1 (Rashi): We challenge R. Eliezer. He is Metamei her even in the days of Zivah, for the first Tana said "all blood that she sees is Tahor", and R. Eliezer refers to this, and says that it is Tamei, and he does not distinguish;

Inference: Even in the days of Zivah she is Teme'ah. R. Eliezer said Dayo (it suffices to be Metaher her in the days of Zivah) according to Rabanan (but he himself is Metamei her in every case).

Explanation #2 (R. Menachem): R. Eliezer is Metamei her only in the days of Nidah, like he said "Dayo" (it suffices to be Metaher her in the days of Zivah).

Implied question: The Gemara asked "we should say that she is Tehorah in the days of Zivah"! (This implies that he is Metamei.)

Answer: This is the conclusion of Rava's words, who said that R. Eliezer defeated Rabanan, for from the verse "Dameha" Rabanan should be Metamei in Yemei Nidah and Metaher in Yemei Zivah;

[The Gemara] answers "Teshev" - one sitting for all of them.

Since we are Metaher in Yemei Zivah due to a Kal va'Chomer, we should be Metaher due to the verse "Teshev" even in Yemei Nidah, for it connotes one sitting for all of them, and we do not distinguish among them;

If so, Dameha comes to teach something else.

Support: We expound like this above in a Beraisa according to Rabanan from "Teshev", that all of her blood is Tahor.

Question: Since if not for the verse "Teshev", even Rabanan would be Metamei due to the verse Dameha, how did they want to make a Kal va'Chomer that even in the days of Nidah she is Tehorah? They said "we answer you with another version [of the Kal va'Chomer]"!

Answer: They challenge him - since the Kal va'Chomer proves that she is Tehorah even in Yemei Nidah, we should say that Dameha comes for a different Drashah.