In Jewish law if the baby is a risk to the health of the mother it must be aborted. But these are very rare scenarios.
If a 19 year old child was truly criminally insane such that he could not differentiate between right and wrong, and posed a direct, immediate threat to the life of his mother, I don't think anybody on this forum would contest a mother's right to use lethal force against her own child to preserve her life.
An unborn child likewise, can not differentiate between right and wrong, and may not pose a knowing threat to his/her mother, but in those exquisitely rare events where the mother's life is threatened by the pregnancy, I don't think anybody would contest her right to terminate the pregnancy.
That said, any exception will be exploited. IIRC, it was Tiller the Killer that justified late term abortions due to the "adverse health effects," on the mother...the adverse health effects he was documenting were headaches.
On the flip side of that coin, you occasionally hear the story of the truly heroic mother who foregoes necessary, life-saving chemo or other necessary procedures/medications due to the dangers posed to their unborn child.