First of all, there is karma involved. Second, there is no Dharma in her nor the people around her. Third, having religion doesnt mean that you will practice especially if you are mentally unwell.
When the problem started (whatever it was), there was no one there to detect nor understand the situation so how can there be help. A lot of people tend to turn a blind eye, when they know something bad is happening and most of them dont care until something bad happens, in this case, the mother killing her child. I think mothers to be or wanna be mothers should go through some counseling and courses to help them understand better what they are dealing with, build a relationship with the mothers to be, understand the person and probably help them when they think that the mothers to be need it.