Yes she should have been jailed.
There are men as Lotta says who have lost everything and then their partners take their kids away, for some men it's the final straw and they kill not only themselves but their children too. So many similar cases involving fathers and I'm sure that in every single case there is an equally sad tale.
However the bottom line is that she took an innocent life. She could not bear for anyone else to have her child so she selfishly took that child's life. There will be a grieving father, grandparents, aunts, uncles etc for whom life will never be the same again.
Yes she is suffering now and will have to live with what she has done for the rest of her life. However justice must be served no matter what state she is in, otherwise what message does that send out? That mothers are to be pitied more than fathers when they commit the same acts of atrocity?
Besides, she won't be in a conventional jail, she'll be in a specialist unit which is probably the best place for her anyway.