I think that's a great argument. I suspect that everything else boils down to that.
Whatever opinion anyone else may have about what happens to the embryo/foetus/baby, the woman gets full control over her body.
Are there any areas where someone doesn't get full control of their body? People can be detained in protective custody, I believe. They can't receive medical treatment without their consent, generally speaking.
I'd say that's a perfectly good, and possibly water tight argument.
I believe that debate demonstrates the strength of the case, rather than suggesting it's weakness.