I think that in most cases where it would be dangerous for the mother to give birth, the baby can be saved by a C section if it's big enough. In the case of something like a tubal pregnancy, then there is no current way to save the baby that I know if and so to save the mother's life, the pregnancy has to be ended anyway. The other big reason why women get abortions is that they feel that something might be wrong with the baby.
This is a bad reason in my opinion because eugenics is never a good thing at any rate and we're not supposed to kill adults because they're sick, only provide care. Some birth defects are so mild they wouldn't really cause too many problems in people's lives. For example I've even heard of people getting abortions because their baby would have a (repairable) cleft palate, or that they would have dwarfism, or some other mild difference.
Many of the syndromes that are most feared (such as Down Syndrome) also come with different levels of severity and some people are quite mildly affected, and even for those who are profoundly disabled, God has chosen to give that person life and it's not right to kill them because they are different. I believe that each person is sent to this world to accomplish some mission and that includes disabled people. Remember that anybody can become disabled at any time and so I think it's wrong to kill someone as a baby and wrong to kill them as an adult because of disabled status. It's true that families of disabled children will need more support and help than other families but this is something that needs to be put in place along with ending abortion. The support system can go hand in hand with banning abortion.