Augustine [AD 354-430] was the Bishop of Hippo Regius and one of the most influential theologians in Western Christendom.
Below is an excerpt from one of his moral treatises which explanations some of the abortion-specific applications of the doctrine of the resurrection from the dead.
84. Now, as to the resurrection of the body, —not a resurrection such as some have had, who came back to life for a time and died again, but a resurrection to eternal life, as the body of Christ Himself rose again,—I do not see how I can discuss the matter briefly, and at the same time give a satisfactory answer to all the questions that are ordinarily raised about it.
Yet that the bodies of all men—both those who have been born and those who shall be born, both those who have died and those who shall die—shall be raised again, no Christian ought to have the shadow of a doubt.
85. Hence in the first place arises a question about abortive conceptions, which have indeed been born in the mother’s womb, but not so born that they could be born again. For if we shall decide that these are to rise again, we cannot object to any conclusion that may be drawn in regard to those which are fully formed.
Now who is there that is not rather disposed to think that unformed abortions perish, like seeds that have never fructified? But who will dare to deny, though he may not dare to affirm, that at the resurrection every defect in the form shall be supplied, and that thus the perfection which time would have brought shall not be wanting, any more than the blemishes which time did bring shall be present: so that the nature shall neither want anything suitable and in harmony with it that length of days would have added, nor be debased by the presence of anything of an opposite kind that length of days has added; but that what is not yet complete shall be completed, just as what has been injured shall be renewed.
86. And therefore the following question may be very carefully inquired into and discussed by learned men, though I do not know whether it is in man’s power to resolve it: At what time the infant begins to live in the womb: whether life exists in a latent form before it manifests itself in the motions of the living being.
To deny that the young who are cut out limb by limb from the womb, lest if they were left there dead the mother should die too, have never been alive, seems too audacious.
Now, from the time that a man begins to live, from that time it is possible for him to die. And if he die, wheresoever death may overtake him, I cannot discover on what principle he can be denied an interest in the resurrection of the dead.
From Augustine’s “Enchiridion”, chapters 84-86