I kind of like the simple "words have meaning" approach, not only in the text of the U.S. Constitution, but also in the observation that: if it's not a "baby", well, then you're not "pregnant".
On the technological front, though, advances in medical science have shown the whole extent of the voodoo in Roe v. Wade. The clearest example I can think of is the ultrasound which has stripped the whole veil of mystery about the unborn child. That was not available in 1973, at least not to the general public.
But science makes no difference to abortion supporters because they are operating on a set of pagan religious beliefs and are completely closed to any facts.