Ok fair, then I think I understand your logic here.
I do see some problems with it, so it may either be wrong, or at least incomplete. Or perhaps simply an unfair characterization of pregnancy. Or maybe its something else where I am wrong and just have not realized it yet. Lets explore if your willing.
So I would argue that its more nuanced than this. it depends largely on what the pregnant lady knew, and when, and how she got pregnant. In certain circumstances this is scenario is harder for me to agree with than others.
For example lets say the woman simply didnt know she was pregnant, or worse yet was raped. In that case its hard to force a child on a woman.
Lets say the situation is such that the woman knew she was pregnant early on, and engaged in unprotected sex, so the pregnancy is largely an act of negligence on her part for not using protection. Furthermore she gets an abortion late int he process with no particular change in her circumstances that would drive her to do so. Lets also assume she could have afforded it. In this scenario I would say it is the fetus who is in the position it is in due to the negligence and willful actions of the mother. As such it would appear, if I am being objective, that making abortion illegal (in this scenario only) would inf act be required to adhere to your own rules, that is, it would be an act of self-defense on the part of the fetus because the fetus is only in the position of being threatened due to the negligence and willful actions of the woman.
So while I do feel we are getting closer to a useful world view it still feels inconsistent or incomplete to me.