Aborting Unpersons - Here's some information on so-called "partial birth" abortions found at Alas, a Blog. Scroll down from the linked entry for a second that is also good. Both posts steal liberally from an article by one John Swomley in the March 1988 Humanist. The linked one gives a list of women who chose late-term abortions, with their reasons and some information on later fertility.

COREEN COSTELLO from Agoura, California. In April 1995, seven months pregnant with her third child, Coreen and her husband Jim found out that a lethal neuromuscular disease had left their much-wanted daughter unable to survive. Its body had stiffened and was frozen, wedged in a transverse position. In addition, amniotic fluid had puddled and built up to dangerous levels in Coreen's uterus. Devout Christians and opposed to abortion, the Costellos agonized for over two weeks about their decision and baptized the fetus in utero. Finally, Coreen's increasing health problems forced them to accept the advice of numerous medical experts that the intact dilation and extraction (D&X) was, indeed, the best option for Coreen's own health, and the abortion was performed. Later, in June 1996, Coreen gave birth to a healthy son.

If the abortions written about are typical, then most late term abortions are performed because the fetus is not viable, which is in itself a danger to the health of the mother. This point is made by Swomley in the second entry:

There are still other questions, such as why not let the woman wait until the thirty-sixth week and go into labor? Fetuses with severe defects have a high chance of dying in utero well before labor begins and therefore create a serious threat to the mother. When a fetus dies, its tissues begin to break down and enter the mother's bloodstream. This can cause clotting problems, making it more difficult for her to stop bleeding. This may then require a surgical delivery or an emergency hysterectomy.

I am pro-choice on self-ownership grounds, regardless of whether or not a fetus is a rights-possessing "person". But I can understand the pro-life position, especially for late-term fetuses - at some point a person does become sacred. I think that is an impossible matter to scientifically determine, but we can at least parameterize it. It's about the mind, which is based on the brain. A human without a brain cannot be a person. A human without a sufficiently well-connected brain cannot be a person. Any abortion ban which ignores those facts is, to me, unacceptable, and I think it should unacceptable as well to any thoughtful person excepting those who believe that every human has a soul including humans lacking a brain. The current bill is an example of such ignorance.