While I believe that the principles of Christian belief inherently lead to a pro-life ethic, I also believe that the foundation for being pro-life is deeper than any one religious belief system, wider than any one political party, and more all-encompassing than anything I can always or easily wrap my mind around.
Being pro-life has little to do with Christian doctrine, because a pro-life stance is never specifically outlined in the Bible. It is not a coincidence that Christians, and members of other religions with roots in Bronze Age cultures, tend toward being pro-life, however, because these religions are founded on inherently misogynistic principles, wherein women are assigned a lesser degree of personhood than men, and the freedom of choice for women is not even a consideration in the construction of a moral framework.
I do think that misogyny, which lies at the heart of all pro-life arguments, like you say, “is deeper than any one religious belief system, wider than any one political party, and more all-encompassing than anything I can always or easily wrap my mind around.” Any instance of trying to deny freedom of choice and total control of one’s own body to each and every woman is an instance of misogyny. It is a an element of a patriarchal system of control and, in the case of Christianity, one that stretches back thousands of years and still aims to convince people that this type of oppression is not only justified, but a form of justice.
In fact, there is no rational, scientific, just argument for a pro-life stance, and jurisdictions where there are greatly expanded abortion rights are doing just fine. The wrath of God is not obliterating them, and their societies are not upending themselves. I’m all for women getting abortions if they want or not getting abortions if they don’t want. Even you acknowledge there are cases where you find abortion acceptable; where you decided to draw that line is arbitrary and is in no way rooted in Christianity. No higher authority sanctioned your personal belief on where the line should be drawn. If you don’t believe me, just try asking ten different Christian ministers. You’ll get ten different answers.
I think we need to reframe this discussion and call it what it is. You are either pro-oppression or pro-freedom. You either believe in oppressing women and denying women the fundamental human right of exercising control over their own bodies, or you believe that women should be free to choose for themselves in all matters concerning their own minds and bodies. The fetus doesn’t even enter into the equation because it is just a fetus. It is not a person.