In the opinion of contemporary rabbinic authorities, is it permissible to perform early pregnancy termination on gentile women? Until what week of gestation and under what conditions?
It might be permissible only if all of the strict conditions listed below are met:
1. The procedure is permitted according to the existing local law.
2. The procedure is permitted according to the religious beliefs of the man and woman involved.
3. The doctor who will perform the procedure has no moral/ethical/conscientious objections to the procedure.
4. The embryonic age is less than forty-one days (from fertilization, which is equal to less than eight gestational weeks).
I would like to add that the stricture of the prohibition against abortion before the end of the eighth week of pregnancy (forty-one days from the moment of fertilization) is always less severe than the stricture of the prohibition of abortion after the eighth week.
For references, please see Nishmat Avraham volume 2, p. 44; vol. 3, p. 234; and vol. 4, pp. 92, 93.