The sin of dying in ‘original sin only’ is the actual mortal sin of omission of never having found sanctifying grace in this life (baptism by water, or desire, or blood) despite ample opportunity. Prenatals, infants and young children who die without baptism do not die in original sin only. (None of the definitions of doctrine on this topic say that they do.) They receive a baptism of blood, just like the Holy Innocents, and so they die in a state of grace and go to Heaven.
If prenatals who die in the womb went to Hell, then that would be tantamount to predestination to Hell, since no baptism of water is possible in the womb. Such a claim contradicts the Magisterial teaching on the universal salvific will of God.
According to CCC 1859
Mortal sin requires full knowledge and complete consent. According to the catholic encyclopedia original sin is
a consequence of this first sin, the hereditary stain with which we are born on account of our origin or descent from Adam.
Original sin is inherited whereas mortal sin is a conscious act and that includes acts of ommission. Therefore, original sin and mortal sin including mortal sins of omission are not the same.
To die in original sin alone means to have no other sin than original sin on the soul.
Pope Eugenius is making a dogmatic definition in the council of Florence when he states that those who die in original sin alone go to hell.
Ron Conte claims that infants cannot die in a state of original sin because they receive a baptism of blood. This is not dogma but speculation. Also
The proposals invoking some kind of Baptism of desire or Baptism of blood, however, involved certain difficulties says THE HOPE OF SALVATION FOR INFANTS WHO DIE WITHOUT BEING BAPTISED
Does then the Council of Florence exclude infants from those who die with original sin alone. It would appear not. Eugenius is very concerned that the baptism of infants should not be delayed and the reason he gives for this is that they may be snatched from the realm of the devil i.e hell. As he is asking for humans to baptise them with water then he is not counting on a baptism of blood or desire to save them.
*With regard to children, since the danger of death is often present and the only remedy available to them is the sacrament of baptism
by which they are snatched away from the dominion of the devil and adopted as children of God, it admonishes that sacred baptism is not to be deferred for forty or eighty days or any other period of time in accordance with the usage of some people, but it should be conferred as soon as it conveniently can; and if there is imminent danger of death, the child should be baptized straightaway without any delay, even by a lay man or a woman in the form of the church, if there is no priest, as is contained more fully in the decree on the Armenians.*council of florence
Not only can children be snatched by the devil but so also can aborted foetuses. Over a century later Pope Sixtus V makes it clear that abortion is wrong not just because it takes life but because the child loses its soul,
Who will not detest such an abhorrent and evil act, by which are lost not only the bodies but also the souls?iteadjmj.com/aborto/eng-prn.html
It is quite clear , therefore that both these popes believed that unbaptised children went to hell. Neither said anything to indicate that they could be saved by baptism of desire or blood.Ron Conte , therefore, has not reconciled the contradiction. Original sin is not a mortal sin of omission and children are included in those who can die in a state of original sin alone and go to hell and further it is dogma…