The complication here is that a responsible, consenting adult tacitly accepts giving up her bodily autonomy (or accepts a risk of doing so) when she has sex.

The complication there is that on the standard view, one cannot give up one's bodily autonomy permanently. You cannot sell yourself into slavery. The pregnant person always has the right to opt-out of the contract.

Though the fetus would presumably be able to get damages. I guess those get paid to the next-of-kin.