Abortion in Jewish Thought and Law
(יט) הַעִידֹ֨תִי בָכֶ֣ם הַיּוֹם֮ אֶת־הַשָּׁמַ֣יִם וְאֶת־הָאָרֶץ֒ הַחַיִּ֤ים וְהַמָּ֙וֶת֙ נָתַ֣תִּי לְפָנֶ֔יךָ הַבְּרָכָ֖ה וְהַקְּלָלָ֑ה וּבָֽחַרְתָּ֙ בַּֽחַיִּ֔ים לְמַ֥עַן תִּחְיֶ֖ה אַתָּ֥ה וְזַרְעֶֽךָ׃

(19) I call heaven and earth to witness against you this day, that I have set before thee life and death, the blessing and the curse; therefore choose life, that thou mayest live, thou and thy seed;

(כב) וְכִי יִנָּצוּ אֲנָשִׁים וְנָגְפוּ אִשָּׁה הָרָה וְיָצְאוּ יְלָדֶיהָ וְלֹא יִהְיֶה אָסוֹן עָנוֹשׁ יֵעָנֵשׁ כַּאֲשֶׁר יָשִׁית עָלָיו בַּעַל הָאִשָּׁה וְנָתַן בִּפְלִלִים. (כג) וְאִם אָסוֹן יִהְיֶה וְנָתַתָּה נֶפֶשׁ תַּחַת נָפֶשׁ. (כד) עַיִן תַּחַת עַיִן שֵׁן תַּחַת שֵׁן יָד תַּחַת יָד רֶגֶל תַּחַת רָגֶל. (כה) כְּוִיָּה תַּחַת כְּוִיָּה פֶּצַע תַּחַת פָּצַע חַבּוּרָה תַּחַת חַבּוּרָה.

(22) And if men strive together, and hurt a woman with child, so that her fruit depart, and yet no harm follow, he shall be surely fined, according as the woman’s husband shall lay upon him; and he shall pay as the judges determine. (23) But if any harm follow, then thou shalt give life for life, (24) eye for eye, tooth for tooth, hand for hand, foot for foot, (25) burning for burning, wound for wound, stripe for stripe.

וא"ל אנטונינוס לרבי נשמה מאימתי ניתנה באדם משעת פקידה או משעת יצירה א"ל משעת יצירה א"ל אפשר חתיכה של בשר עומדת שלשה ימים בלא מלח ואינה מסרחת אלא משעת פקידה אמר רבי דבר זה למדני אנטונינוס ומקרא מסייעו שנאמר (איוב י, יב) ופקודתך שמרה רוחי

Antoninus asked Rebbe: "At what point is the soul given to a human? Is it from the moment of decree [that such a child will exist], or from the moment of formation?" He responded: "From the moment of formation." Antoninus replied, "Is it possible that a piece of meat can last for three days without salt, and yet not become rotten? Rather it must be from the moment of decree." Rebbe said: "I learned this thing from Antoninus, and there is a verse which supports him: 'Your Providence has guarded my soul' [Job 10]."

מתני' גהאשה שיצאה ליהרג אין ממתינין לה עד שתלד האשה שישבה על המשבר ממתינין לה עד שתלד האשה שנהרגה נהנין בשערה בהמה שנהרגה אסורה בהנאה: גמ' פשיטא גופה היא איצטריך ס"ד אמינא הואיל וכתיב (שמות כא, כב) כאשר ישית עליו בעל האשה ממונא דבעל הוא ולא ליפסדיה מיניה קמ"ל

Mishnah: If a woman is about to be executed, one does not wait for her until she gives birth. But if she had already sat on the birthstool, one waits for her until she gives birth. If a woman has been put to death one may use her hair; if an animal has been put to death it is forbidden to make any use of it.

Gemara: But that is self-evident, for it is her body! It is necessary to teach it, for one might have assumed since Scripture says: According as the woman's husband shall lay upon him, that it (the unborn child) is the husband's property, of which he should not be deprived, therefore we are informed (that it is not so).

(ו) האשה שהיא מקשה לילד, מחתכין את הולד במעיה ומוציאין אותו אברים אברים, מפני שחייה קודמין לחייו. יצא רבו, אין נוגעין בו, שאין דוחין נפש מפני נפש.

(6) A woman who was having trouble giving birth, they cut up the fetus inside her and take it out limb by limb, because her life comes before its life. If most of it had come out already they do not touch it because we do not push off one life for another.

Responsa Tzitz Eliezer 13:102

It is clear that in Jewish law an Israelite is not liable to capital punishment for feticide.... An Israelite woman was permitted to undergo a therapeutic abortion, even though her life was not at stake.... This permissive ruling applies even when there is no direct threat to the life of the mother, but merely a need to save her from great pain, which falls within the rubric of "great need." Now, is it possible to imagine a case in which there is more need, pain, and distress, than the present one, in which the mother is confronted by the [prospect of a] suffering child whose certain death is only a few years away and nothing can be done to save it?