How does a society make murder of a particular segment of that society palatable? For as a whole, with a few exceptions, people and cultures restrict the legitimate purposeful killing of another person to defense of self, community or nation.
To legitimize the abortion - murder of the unborn requires the expansion of self defense to include the right of the individual to determine what actions or conditions determine the cause to murder. It is given a name-reproductive rights- so that it is exempt from "thou shalt not kill."
Being named, some of the causative factors that would lead to such action could be enumerated, such as personal discomfort, undesired responsibility, restrictions on one's life in any way, societal or peer group pressure, or any other seemingly appropriate at the time.
Yet there will still be those who hold to the "outmoded" idea of the sanctity of life, that man was created in the image of God and thus resist the act of killing another human.
Not a problem, use the tried and true method - dehumanize the unborn or even unwanted newly born. The method was successfully used by slaveholders, made popular by the proponents of the "science" of eugenics, and that master of the art, Adolph Hitler.
The fetus is no longer a stage in the development of a human, it is an unwanted growth like a tumor and can be excised with the same lack of compassion. It makes no difference if it feels pain, is in the birth canal, or even alive after a botched procedure.
Having established in the case of the unborn, or even in some cases unwanted newly borns, that they no longer have value as humans. Only the individual as "mother" can really determine that. Life is not sacred, only an option exercised by another. So the precedent has been established what is the next group to be dehumanized, the old, the infirm, the mentally restricted? Before long we might be killing Jews.