Asalam Walikum, I was wondering why abortion is haram? I feel as if it's a woman's choice on whether she wants to keep it or not. Even if they kept it for society sake they would not really be as happy at all.
Alaikumassalam wa rahmatullah,
Abortion is permitted when it is necessary, as discussed on my Islam and abortion page.
The reason why abortion is not a simple choice is because it may involve another human life (the fetus). The Quran tells us that killing a single innocent soul is like killing all of mankind, which means that each soul is of infinite worth. When dealing with souls, we cannot decide to kill one when we like. As an example, even if a country can acquire all the wealth in the world by killing a single innocent person, Islam forbids them from doing it.
So if the fetus is a soul, then aborting it would be killing a soul. Since we have no certain information on the status of the fetus as a soul and the point where it really becomes a human soul, the pious thing to do is to avoid abortion unless it is absolutely necessary.
As for a woman not being happy with the child, that is a very minor matter compared to the issue of life and death. You cannot just murder a potential human child because the mother may not like it or find it a burden. This act could be similar to the pagans burying their infant daughters because they were ashamed that their wives gave birth to a daughter.