From "Induced Abortion," The Journal of Halacha and Contemporary Society Vol. 1 No.1, Spring 1981

"Indications for induced abortion can be divided into two categories, maternal and fetal...

a.) Maternal indications for abortion:

The mother's life is endangered as a result of pregnancy or delivery.
The mother's life is endangered by a disease pre-dating the pregnancy, which is exacerbated by it.
A maternal systemic organic disease, exacerbated by pregnancy, but not life-threatening.
Hastening of maternal death as a result of pregnancy.
Maternal mental disease cause or exacerbated by pregnancy.
Organic disease of an isolated organ, exacerbated by pregnancy.
Extra-marital pregnancy.
Social, economic, or other factors.

b.) Fetus-related reasons for abortion: