in my model, i try to avoid granular details re rights.
the aim is to provide a simple right to a choice during a time window; and to associate that choice with the responsibility to know your condition.
i am not sure why any woman with a normal pregnancy would need more time.
after that, i would allow only narrow exceptions for life of the mother and a small set of major birth defects. maybe a few other things.
i admit that i presume free choice is available for everyone. and so caged victims may have an issue. but that is more or less as likely to be a problem at 30 weeks as at 12.