Islam values human life. This is clearly expressed in the Qur'an where we are told that in the sight of God killing a human is a very serious matter (see Qur'an 5:32). 

The Qur'an teaches that on the Day of Judgement
parents who killed their children will be under trial for that crime and
their children will be witnesses against them (see Qur'an 81:8-9). 

People often fear that having more children will make them poor. In reply to that, the Qur'an says: ''Do not slay your children for fear of poverty. We shall provide for them and for you" Qur'an 17:31). 

Even in a case where one is already poor, the Quran insists that Allah will provide sustenance for us and for our children, and furthermore that Allah has made human life sacred (see Quran
6:151). 

The right to life is God-given. No human should take away that right. The general rule, herefore, is that abortion is not permitted in Islam. 

However, Islam is a very practical religion.It includes principles to deal with exceptional cases. One such principle is that when a pregnancy threatens the life of the mother, an abortion
may be performed. Although the lives of both mother and child are sacred,in this case it is better to save the principal life, the life of the mother.
Even in this case, it would be better if the abortion is done before thefoetus is 120 days old, for that is when the soul is breathed into the foetus. Islam does not permit abortion in other cases. 

Women who have been victims of rape or incest naturally deserve sympathy and help. But a child conceived in this unfortunate manner still has a right to live. Of course this places an unwanted burden on the mother, but killing the child is not the right solution. 

To understand this point better, suppose someone sees the poorer sections of society as an unwanted burden on the rich. Would it be right then to kill off all the poor? Of course not. Why
then should anyone decide that a child should be killed just because of being an unwanted burden? 

Society as a whole should help such a mother and relieve her as far as possible. But the child should not be killed. 

Furthermore, the fact that such cases occur is an indication that people desperately need spiritual food. They need the pure teachings that will help people turn their minds away from adultery,rape, and incest. People need God.