Christopher Kaczor, the author of The Ethics of Abortion, writes the following in the subject piece:
The common intuition "shared, in general, by advocates and opponents of abortion alike” that late abortion is worse than early abortion seems to undermine the basic equality of all human beings and to help justify early abortion. In fact, it implies no such thing. Circumstantially, no two cases of intentional killing of the innocent are exactly alike. Intrinsically, however, every case is identical, as an act that unjustly deprives the victim of life. That it is worse to kill a human adult than to kill a human being in utero, and worse to kill a child already born than to kill one at the embryonic stage, does not in any way justify the killing of the latter.
You can read Kaczor's piece in its entirety here.
Stand firm in Christ and stand firm for the reborn,