Aborting the Messiah and forcing Him to undertake His ministry so very prematurely did more than just mean He’s a lot shorter. It also altered the whole support structure that God had ordained for His ministry and eventual crucifixion. According to the plan, when Jesus began preaching He’d start by getting baptized by his cousin John, who’d already be doing a big “coming attractions” speaking tour for the Christ. Not so in this case.
Fetus Christ’s last comment on this page reflects an interesting point of debate. There is no mention of abortion anywhere in His teaching or the preaching of His apostles, despite the fact that miscarriage-inducing herbs were in common use at the time (think “Plan B/morning after pill”, but with less safety and less effectiveness).
The only Biblical passage that specifically mentions abortion or miscarriage is Exodus 21 (source of the famous “an eye for an eye, a tooth for a tooth” catchphrase), in which God establishes the punishments for certain crimes. The punishment for premeditated murder: death. For accidental killing: exile. For maiming a slave: let him/her go free. And for causing a miscarriage: paying the would-be father a fine. So apparently the nuts who try to assassinate doctors who perform abortions… are going a little above-and-beyond.