How does Islam deal with abortion in cases of rape or incest?

Scholars have unanimously agreed that it is impermissible and completely prohibited to conduct an abortion if the age of the fetus has reached 120 days. This is because it is considered killing a soul which Allah has forbidden, except by right. Allah says in the holy Qur`an:

"And do not kill your children out of poverty; We will provide for you and them." [6: 151] and,
"And do not kill the soul which Allah has forbidden, except by right." [17: 33].

Otherwise, scholars have disagreed on the permissibility of abortion if the fetus has not completed 120 days inside its mother's womb. Some of them deemed abortion prohibited and this is the relied upon opinion of the Malikis, Zahiris and some of the Shafi'is.

Other scholars maintained that abortion is absolutely disliked and this is the opinion of some Malikis and others maintained that it is permissible when there is an excuse and this is the opinion of the Hanafis and Shafi'is. According to Hanafis, pregnancy out of wedlock [zina] is a valid excuse for conducting an abortion.

According to the preponderant opinion implemented for fatwa, abortion is absolutely prohibited whether before or after the fetus ensoulment except if there is a necessity permitted in the shari'ah. This necessity is when a trustworthy physician decides that the continuation of pregnancy imposes risk to the mother's life or health. Thereupon, it is permissible to conduct an abortion to preserve the mother's life and keeping the stability of her health since the mother's life takes precedence over the fetus unstable life.

The Islamic Fiqh Assembly of the Muslim World League based in Mecca has decided the following: "If the fetus has reached 120, it is impermissible to conduct an abortion even if it is medically diagnosed with congenital defects. However, if a committee of specialized physicians decided that the continuation of pregnancy imposes risk to the mother's life. In this case, it is permissible to conduct an abortion whether or not the fetus was deformed to undertake the lesser of two harms".