Note at the outset: It is a common sin among both Jews and Noahides to end a pregnancy for unjustified reasons. A competent Torah-Observant, that is to say, “Orthodox” Rabbi should be consulted on this sensitive topic. For fear that my original article on “the Status of the Embryo – Before 40 Days & After 40 Days – When a Daughter of a Priest Marries a Regular Israelite” would not be interpreted correctly I decided to switch to a related topic
Talmud, Sanhedrin 92b as translated by Sefaria.org
(Note: Only the parts in bold are the actual words, the other parts are commentary by Sefaria.org. The explanation of formation used by Sefaria.org is based on Maharsha. It is possible that Rashi might have a separate definition.)
And Antoninos said to Rabbi Yehuda HaNasi: From when is the soul placed in a person? Is it from the moment of conception or from the moment of the formation of the embryo, forty days after conception? Rabbi Yehuda HaNasi said to him: It is from the moment of the formation of the embryo. Antoninos said to him: That is inconceivable. Is it possible that a piece of meat could stand for even three days without salt as a preservative and would not rot? The embryo could not exist for forty days without a soul. Rather, the soul is placed in man from the moment of conception. Rabbi Yehuda HaNasi said: Antoninos taught me this matter, and there is a verse that supports him, as it is stated: “And Your Providence [pekudatekha] has preserved my spirit” (Job 10:12) indicating that it is from the moment of conception [pekida] that the soul is preserved within a person.