"...דְּסָתִיר בִּנְיָינָא דְּקוּדְשָׁא בְּרִיךְ הוּא וְאוּמָנוּתָא דִּילֵיה" תמר לזר

From "pregnant" — in any event. "and there be no death": in the woman. "then he shall be punished": for the fetuses (i.e., payment for the fetuses shall be exacted of him.) You say this, but perhaps (the meaning is that there be no) death in the fetuses, then he shall be punished for the woman? It is, therefore, written (Ibid. 23) "And if there be death, then you shall give a life for a life" (which, perforce, refers to the life of the woman) __ But perhaps (the meaning is) if there be no death either in the woman or in the fetuses, (then he must pay; but if there is death in either, he is put to death and there is no payment.) __ But if you say this, he (the father) must pay the midwife (for delivery of the fetuses). (How, then, is "he shall be punished" to be understood?) How, then, must the verse be understood? "and there be no death" — in the woman; "then he shall be punished" — for the fetuses.

(3) ...A baby boy, even one who is one day old, becomes impure ... and one who kills him is liable for his murder, as it is written: “And he that smites any man mortally shall be put to death” (Leviticus 24:17), i.e., any man, including a child who is one day old; ...

(6) If a woman is having trouble giving birth, they cut up the child in her womb and brings it forth limb by limb, because her life comes before the life of [the child]. But if the greater part has come out, one may not touch it, for one may not set aside one person's life for that of another.

its head came out: With a women that is experiencing difficulty giving birth and is in [mortal] danger. And it is taught in the first section [of this teaching], "the midwife extends her hand and cuts it up and extracts [the pieces];" as the entire time that that it has not gone out into the air of the world, it is not [considered] a soul, and [so] it is possible to kill it and to save its mother. But when its head came out, we cannot touch it to kill it, as it is like a born [baby]; and we do not push off one soul for the sake of another. And if you will ask [from] the story of Sheva ben Bichri - [wherein it is written] (II Samuel 20:21), "behold, his head is sent to you" - they pushed off one life for the sake of another; there, it was because even if they had not delivered him, he would have been killed in the city when Yoav would have seized it, and they would have been killed with him. But if he would have [otherwise] been saved - even though they would have been killed - they would not have been allowed to deliver him [to Yoav] in order to save themselves. And also (another answer) is that it is because he was a rebel to the kingdom, and so is it explained in the Tosefta (of Terumah).

(3) A baby boy, even one who is one day old, becomes impure... and one who kills him is liable for his murder, as it is written: “And he that smites any man mortally shall be put to death” (Leviticus 24:17), i.e., any man, including a child who is one day old;

MISHNA: In the case of a pregnant woman who is taken by the court to be executed, the court does not wait to execute her until she gives birth. Rather, she is killed immediately. But with regard to a woman taken to be executed who sat on the travailing chair [hamashber] in the throes of labor, the court waits to execute her until she gives birth.

Rav Yehuda says that Shmuel says: In the case of a pregnant woman who is taken by the court to be executed, one strikes her opposite the womb, i.e., on the abdomen, so that the fetus dies first and so that she not suffer disgrace as a result of publicly bleeding from labor.

In the case of the daughter of a priest who married an Israelite and her husband died on that same day, she immerses to purify herself, as she is ritually impure due to their intercourse, and she may partake of teruma that same evening? Evidently, the Sages were not concerned that she became pregnant from the initial act of intercourse, even that of marriage. Rav Ḥisda said: She immerses and partakes of teruma only until forty days after her husband’s death, when there is still no reason for concern, as if she is not pregnant then she is not pregnant. And if she is pregnant, until forty days from conception the fetus is merely water. It is not yet considered a living being, and therefore it does not disqualify its mother from partaking of teruma.

The Gemara asks: And how much time must pass for the fetus to be known? Sumakhos says in the name of Rabbi Meir: Three months.