Rav Yehoshua Yeshaya son of Rav Aharon Neuwirth writes in his book on the laws of Shabbat“Shemirat Shabbat Ke – Hilchata” Chapter 36, Halacha 2
We violate Shabbat to save a fetus, even if the fetus is less than 40 days old. A pregnant woman that is bleeding, since there are cases that one can desecrate Shabbat (to solve her medical issues) one should clarify by a doctor and by an authoritative Rabbi who issues Psak Halacha, what is permitted to do on her behalf on Shabbat.
Among the sources that Rav Neuwirth cited in a footnote is Be’ur Halacha of the Mishna Brura to Shulchan Aruch, O.C. 330:7, on the section starting with the words או ספקAmong the sources for Be’ur Halacha is “the Ran” (Rabbeinu Nissim) in his comments to the Rif on Yoma 3b. There “the Ran” provides 3 proofs that on the one hand in a situation where a Jew killed a fetus that has not left the womb, he is not classified together with the person who killed a one day old baby. On the other hand “the Ran” said, regarding Shabbat, “desecrate on his behalf one Shabbat, for perhaps he will observe many Shabbats (Sabbaths), therefore we do this even for a fetus less than 40 days…”However, “the Ran” suggests a second possibility that maybe, the threat to the fetus is linked to a threat to the mother’s health. See there for details.
Question: Is the Halacha exactly the same for a Non-Jewish Fetus?
Answer: No!
Vilnagaon.org will leave it to others to explain in what way.