I wish it were possible to register a wanted pregnancy. That way, as early as you know you're pregnant, you could go down to the courthouse and get a paper that registered the embryo/fetus as human. At that point you have to wear, say, a blaze-orange vest at all times. If you are caught smoking, you are Endangering the Welfare of a Minor, and if a courier on a bike hits you and you miscarry, it's accidental murder. If you miscarry all by yourself, it would be investigated as any other sudden death, and you might be found guilty of manslaughter, just as might happen if you had caused anyone else's death through no fault of your own. But if you aren't sure you want this particular pregnancy to continue, you don't register it; at that point abortion is a perfectly viable (oops) option, whereas it would not be for a registered pregnancy. Women who are anti-choice or anti-abortion could register all their pregnancies; women who were pro-choice might wait to see if they think they want this one.
If a registered pregnancy is found to be in distress (and things like spina bifida might not show up till third trimester), the options are then very narrow, as you would then be contemplating a mercy killing. But the laws governing mercy killings would come into play, and if (say) your state allows the turning off of life support for the terminally ill, you should be allowed to do something (RU 486?) that will destroy the placenta or something (which effectively turns off the fetus' life support). If you aren't allowed to do it for your grandfather, you wouldn't be allowed to do it for your about-to-be-a-vegetable child. But that makes the definition of when a fetus (or even embryo) becomes a human being a LEGAL one, just like the definition of a human being anyway - it didn't used to include blacks, or women, and so on. But it could be up to the INDIVIDUAL to decide, not the government, and both sides would have part of what they wanted...

Personally I am pro-choice and believe that abortion should be available on demand at any point in the pregnancy. I believe a fetus is a body part of the woman until birth, and that she should have total control over her own body. (I wouldn't outlaw suicide, either.) I would use education to minimize the numbers of women who would wait till after Quickening to decide. I have a sister who used abortion as a method of birth control for years, I disapproved of it and had little sympathy later when she developped dysmenorrhea, but would have argued vociferously for her right to continue to do so. I have never had an unwanted pregnancy, and have miscarried one wanted one and one I was very glad to lose. In case anyone wonders where I'm coming from, as it were.

I also stress that what I believe are my OPINIONS. I would never try to convince anyone with different OPINIONS that they were wrong, but don't consider any other views on this issue to be anything other than opinion... In fact, I am pro-choice of opinions, too.