The baby is not in a plastic bag, the baby is behind a clear drape so the mother can see what is going on. And even after the child is born, the doctor is still sterile and so is the incision on her abdomen they likely still have to close the section. Source: I operate

I think it’s more likely that this woman had a C section and the baby was still in the sterile environment - hence why she’s wearing an OR scrub cap and the blue drapes.