“Church leaders have said that some exceptional circumstances may justify an abortion, such as when pregnancy is the result of incest or rape, when the life or health of the mother is judged by competent medical authority to be in serious jeopardy, or when the fetus is known by competent medical authority to have severe defects that will not allow the baby to survive beyond birth. But even these circumstances do not automatically justify an abortion. Those who face such circumstances should consider abortion only after consulting with their local Church leaders and receiving a confirmation through earnest prayer.
When a child is conceived out of wedlock, the best option is for the mother and father of the child to marry and work toward establishing an eternal family relationship. If a successful marriage is unlikely, they should place the child for adoption, preferably through LDS Family Services (see “Adoption”).” http://www.lds.org/study/topics/abortion?lang=eng