Pro-choice.
Personally, I believe that abortion is fine, but it shouldn't happen purely because the foetus will be born with a survivable disability, as this just doesn't sit well with me. If there are other reasons to go through with the abortion then fine, but if the pregnancy was planned or wanted before the discovery of the disability then the family should really go through with it, as planned pregnancy generally involves being prepared to look after the planned child no matter what.
I can see where pro-lifers are coming from with the whole murder argument, but I think that as long as the foetus is not considered medically 'brain-living' (as opposed to brain dead) then it's not murder. Lack of cognitive brain function is a requirement of death in terms of medicine, so therefore the foetus is not alive at this stage and it cannot be considered as murder.
I'm not sure when cognitive functions begin, but even if that has already happened then I think it's up to the family and primarily the woman to make the choice. There are always exceptional circumstances and I believe the rights of a living mother precede the rights of an unborn foetus. Women should not be forced to go through pregnancies if they don't wish to, especially if that pregnancy will be harmful to themselves, both physically and emotionally.
It's also important that women are not 'blamed' by pro-life organisations for abortions, as it is a difficult decision to make even when a staunch supporter of the pro-choice argument.