An argument could be made that by engaging in consensual sex with full knowledge of that having sex could lead to the creation of a life that would be dependent on her for 9 months, she implicitly consented to abstain from killing that life because it's dependent status is directly due to her (and her partner's action).

Bodily autonomy is also not an ascendent right that trumps all else. For example, we violate the bodily autonomy of prisoners who do not wish to be vaccinated while they are institutionalized in the interest of public health. I would even argue that mandatory vaccinations are an even greater violation of bodily autonomy than banning elective abortions because mandatory vaccination is a forced medical procedure while banning elective abortions is just forcing someone to temporarily abstain from an action that would harm someone else but does not force any sort of medical treatment on the woman.