One of the most horrible aspects of aborting a baby—or suffering a miscarriage—is that the poor child is not able to be baptised. A baptism can only be performed on a living subject.
Instead of going straight to Heaven like a deceased, baptised infant does, the fate of the aborted baby’s soul is uncertain. It is unlikely that he sees God face to face. It is thought that the soul of an aborted baby goes to a place of natural happiness (that is, something like the experience of a very happy earthly life), but with neither the vision of God, nor a complete union with Him.
The reason why abortion is a tragic act is that the baby is deprived of this most important and primal Sacrament and, as a result, the beatific vision of God; it is an act which is of everlasting adverse consequence.