Look to other examples of bodily autonomy that we already use in the medical fields and you will find the counter argument. Specifically around autonomy and those in an induced coma and how decisions are made for the state of which the person in an unconscious state, which is always to assume that the person would rather be in the state they possessed prior to being placed into an induced coma.

The conversation of when life starts is irrelevant because there are is no analogous standing for this argument in the medical field. There are no medical standings where we prioritize a non-autonomous, non-decision making body over that of a mother who is exactly all of those things, it's rather simple logic and there is precedent for this argument. The counter argument cannot contest this with any real life examples.