pobaciti

1. (spontaneously) to miscarry; to have a miscarriage
   Nažalost, pobacila je u trećem mesecu. — Sadly, she miscarried in the third month.
2. (deliberately) to have an abortion
   Odlučila je da ne pobaci i da rodi dete. — She decided not to have an abortion and to have the baby.

The word covers both miscarriage and abortion; context shows which is meant.