Jesus said that we should forgive seventy times seven. So we are supposed to forgive the mother who is having an abortion.
There is no sin or immoral action if you do not know what you are doing is wrong. Those mothers are lied to by the doctors who do the abortion to them, they tell them that they just have tissue and blood inside of them.
Although a lot of these mothers feel guilty and depressed, they are not completely to blame what they do, so what we should do is give support and information to them, because when they have the appropriate knowledge of what are they going to do, they can reach all the truth, and become free.