LOL you have to admit that pretending you are pregnant for months then going out and kidnapping a pregnant woman, then cutting into her to take her baby is a bit off.
But to pass an insanity defense, she will have to prove she was incapable of knowing right from wrong. And hiding the woman's body in the basement when she called 911 about the baby is a good indication that she did know right from wrong.
I do wonder though. She obviously wanted to hide the mother and her death. But she wanted to acknowlege the baby's death. She probably wanted the sympathy for having the stillborn baby. I wonder if she felt grief over the loss of the baby or if she really felt relief. Here she had all the credit for the pregnancy and anticipating the sympathy for the death, yet she didn't have the bother of caring for a newborn.