There seem to be very few statements in ancient literature on Jewish attitudes to abortion. Here is what I have been able to find. I have not included material from the Mishnah or Talmud, which I may include in a separate post.
For reference, here’s the Masoretic text of Exodus 21:22-25 (RSV).
22 “When men strive together, and hurt a woman with child, so that there is a miscarriage, and yet no harm follows, the one who hurt her shall be fined, according as the woman’s husband shall lay upon him; and he shall pay as the judges determine. 23 If any harm follows, then you shall give life for life, 24 eye for eye, tooth for tooth, hand for hand, foot for foot, 25 burn for burn, wound for wound, stripe for stripe.
The Septuagint version (NETS) is slightly different:
22 Now if two men fight and strike a pregnant woman and her child comes forth not fully formed, he shall be punished with a fine. According as the husband of the woman might impose, he shall pay with judicial assessment. 23 But if it is fully formed, he shall pay life for life, 24eye for eye, tooth for tooth, hand for hand, foot for foot, 25 burn for burn, wound for wound, stripe for stripe.
Philo, The Special Laws, book 3, 108-9, 117-8 (online here):
(108) But if any one has a contest with a woman who is pregnant, and strike her a blow on her belly, and she miscarry, if the child which was conceived within her is still unfashioned and unformed, he shall be punished by a fine, both for the assault which he committed and also because he has prevented nature, who was fashioning and preparing that most excellent of all creatures, a human being, from bringing him into existence. But if the child which was conceived had assumed a distinct Shape in all its parts, having received all its proper connective and distinctive qualities, he shall die; (109) for such a creature as that is a man, whom he has slain while still in the workshop of nature, who had not thought it as yet a proper time to produce him to the light, but had kept him like a statue lying in a sculptor’s workshop, requiring nothing more than to be released and sent out into the world.
XX. (110) On account of this commandment he also adds another proposition of greater importance, in which the exposure of infants is forbidden, which has become a very ordinary piece of wickedness among other nations by reason of their natural inhumanity; (111) for if it is proper to provide for that which is not yet brought forth by reason of the definite periods of time requisite for such a process, so that even that may not suffer any injury by being plotted against, how can it be otherwise than more necessary to take similar care of the child when brought to perfection and born, and sent forth…
(117) Therefore, Moses has utterly prohibited the exposure of children, by a tacit prohibition, when he condemns to death, as I have said before, those who are the causes of a miscarriage to a woman whose child conceived within her is already formed. And yet those persons who have investigated the secrets of natural philosophy say that those children which are still within the belly, and while they are still contained in the womb, are a part of their mothers; and the most highly esteemed of the physicians who have examined into the formation of man, scrutinising both what is easily seen and what is kept concealed with great care, by means of anatomy, in order that, if there should be any need of their attention to any case, nothing may be disregarded through ignorance and so become the cause of serious mischief, agree with them and say the same thing. (118) But when the children are brought forth and are separated from that which is produced with them, and are set free and placed by themselves, they then become real living creatures, deficient in nothing which can contribute to the perfection of human nature, so that then, beyond all question, he who slays an infant is a homicide, and the law shows its indignation at such an action
Josephus, Antiquities book 4, 278 (at Lacus Curtius here, as chapter 8, 33):
He that kicks a woman with child, so that the woman miscarry, (29) let him pay a fine in money, as the judges shall determine: as having diminished the multitude by the destruction of what was in her womb: and let money also be given the woman’s husband by him that kicked her: but if she die of the stroke, let him also be put to death. The law judging it equitable that life should go for life.
Josephus, Against Apion book 2, 202 (Lacus Curtius here, ch. 25) (which begins with an interesting statement on homosexuality also):
The law moreover enjoins us to bring up all our offspring: and forbids women to cause abortion of what is begotten; or to destroy it afterward. And if any woman appears to have so done, she will be a murderer of her child; by destroying a living creature, and diminishing human kind.
In the Sentences of pseudo-Phocylides, verses 184-5 (via Walter T. Wilson, The Sentences of Pseudo-Phocylides, de Gruyter (2005) p.187):
184 A woman should not destroy an unborn babe in the womb, 185 nor after bearing it should she cast it out as prey for dogs and vultures.
The Sybilline Oracles, book 2 (via Sacred Texts here, Milton S. Terry, 1899):
315 … and the godless furthermore
Shall to all ages perish, all who did
Evils aforetime, and …
345 And all who loosed the girdle of the maid
For secret intercourse, and all who caused
Abortions, and all who their offspring cast
Unlawfully away; and sorcerers
And sorceresses with them, and these wrath
350 Of the heavenly and immortal God shall drive
Against a pillar where shall all around
In a circle flow a restless stream of fire;
There are further quotations on when an unborn child gains a soul, or is legally considered a separate person, but I have not included these here. A number of these are listed in Gorman, The Early Church and Abortion, IVP (1982), repr. Wpif & Stock (1998).