Unlike most conservative Christian denominations, Orthodox Judaism tends to be more hedged in its opposition to abortion. Gidon Rothstein analyzes an essay on the subject by the late Aharon Lichtenstein, one of the greatest Modern Orthodox talmudists. In brief, Lichtenstein’s reading of halakhah generally permits abortion until the 40th day from conception, forbids it in all but extreme cases in the third trimester, and entertains a variety of reasons to allow it, in specific circumstances, during the intervening period. Rothstein writes:
Lichtenstein closes [his essay] with two general points. First, he has left some areas of the discussion not fully determined. This was not out of any hesitation to come to conclusions, but because he thinks [halakhic decisions] cannot be painted with too broad a brush, which is why he was always . . . insistent on laying out parameters rather than giving firm answers; the flexibility in the sources means the same rabbinic authority might in one case prohibit an abortion but in another case . . . allow it.
He wrote as he did to leave room for human input into decisions, which is how halakhah is supposed to work. . . .
Without apologizing, he did note that the “liberal” view on this issue comes at the expense of the humanity of the fetus. In order to allow the mother to do what she feels right, the liberal view had to ignore or dismiss the concerns and humanity of the fetus.
In arguing that the decision often [should] go the other way, Lichtenstein closed by reminding his listeners and readers that this isn’t only out of obedience to the will of God, but is also an expression of halakhah’s concern with human dignity and welfare, which “rises up in indignation against the torrent of abortions.”