Point 1: circumstances and experiences during pregnancy have an influence on the later development of the child, do it is not completely irrelevant. However, I agree that the baby cannot leave the mother until birth, so "imprisonment of the baby" is a very week argument.

Point 2: not only the baby, but the mother as well!

Point 3: the defendant claims, that she was attacked and defended herself and the baby with a single shot. There is no verdict in the case, yet, so far she is only indicted. That means she has to be considered innocent until proven otherwise.

In other words: if she is convicted, then you are right. Until then, the child should stay with the mother, except if there is any indication for neglect or mistreatment. An alternative might be the father, but you should have very good arguments to separate mother and child, and for me, that means you should have very good arguments to keep the mother imprisoned until the process.

If you ignore the "the fetus is a person" discussion, the critical point remaining is the inadequate medical care.

So in this case it would be easy, ensure proper medical care, topic closed.

Once you make a fetus a person, the legal context gets complicated. Good work from the attorney, their job is to use anything they can to help their client. So no matter if the law or legal philosophy behind it is stupid, if it is there, use it.

Regarding the question if it is acceptable to release her, (again, ignoring the fetus discussion), I think the real question is why she is held in jail in the first place. From what I see in the article, the discussion between prosecutor and defence is, if she acted in self defence or with malicious intent. Does not immediately scream "cold blooded serial killer" to me. So something like house arrest with ankle monitor could be a better approach. But the question is, why this option was not chosen in the beginning.