I never said I don't believe in Limbo.  What I said was:
"I was taught Limbo was only used before the resurrection and ascension and is now closed."

Doing a quick search, I found this explanation:

In theology, the word limbo, derived from the Latin limbus, meaning “hem” or “border,” is understood in two senses:  First, limbo refers to the temporary place and state of rest of the souls of the just who had died and were awaiting the saving action of the Messiah.  Once our Lord had offered Himself on the cross as the perfect sacrifice for our sins, He “descended into Hell,” as we profess in the Apostles’ Creed, to reveal Himself and to take these souls to Heaven.  (The word Hell here should not be confused with our present understanding as the place of eternal damnation; here Hell is the English translation for the word sheol, “the place of the dead,” with limbo being the particular waiting place for the just.)  This understanding of limbo is denoted as limbus patrum.

The other understanding of limbo refers to the permanent place and state of the souls of those who have died without baptism and without mortal sin, particularly the souls of infants.  These souls are denied eternal life in Heaven and the Beatific Vision due solely to the effects of Original Sin.  This understanding of limbo is denoted as limbus infantium or limbus puerorum.

At the outset of this article, note that the Church has never officially defined the doctrine of limbo.  Rather, limbo is a theological supposition that became a popular way of dealing with a teaching of our Lord regarding the necessity of baptism for eternal salvation and what happens to the souls of individuals who die without being baptized.

Jesus taught, “I solemnly assure you, no one can enter into God’s kingdom without being begotten of water and Spirit” (John 3:5).  The Catechism consequently asserts, “The Lord Himself affirms that Baptism is necessary for salvation. …The Church does not know of any means other than Baptism that assures entry into eternal beatitude; this is why she takes care not to neglect the mission she has received from the Lord to see that all who can be baptized are ‘reborn of water and the Spirit’” (#1257).

Given the Lord’s teaching, the problem comes to mind, “What happens to a baby who through no fault of his own is born with Original Sin and who dies without the benefit of baptism?”  Several of the early Church Fathers addressed this issue.  St. Gregory nαzιanzen (d. 389)  posited, “It will happen, I believe, …that those last mentioned [infants dying without baptism] will neither be admitted by the just judge to the glory of Heaven nor condemned to suffer punishment, since though unsealed [by baptism], they are not wicked. …For from that fact that one does not merit punishment it does not follow that he is worthy of being honored, any more that it follows that one who is not worthy of a certain honor deserve on that account to be punished” (Orations, XL, 23).  Tertullian (d. 250) and St. Ambrose (d. 397) agreed that only those souls culpable of unrepented mortal sin would be damned to Hell.  Given this line of thought, the idea of some intermediary place or limbo existed for these souls.

On the other hand, St. Augustine (d. 430) denied any notion of such an intermediary place or limbo.  He believed that unbaptized children would be sent to Hell since they did not merit Heaven due to Original Sin and not to Purgatory since that period of purification eventually leads to Heaven.  However, he conceded that their punishment would be the mildest of all (De peccatorum meritis, I, xxi).
Dissatisfied with St. Augustine’s harsh teaching, the Scholastics of the Middle Ages, including St. Anselm (d. 1099), Abelard, and Peter Lombard, revisited the issue.  St. Thomas Aquinas (d. 1274) laid the foundation for the “limbo” explanation.  He emphasized that Original Sin was a sin of nature inherited from our parents rather than a sin freely committed.  Since Hell was the place of eternal punishment for unrepentant mortal sinners who had rejected God and since the unbaptized could not enter Heaven, those unbaptized infants should be in another place, perhaps in a place and state of limbo.  While he also believed that the loss of Heaven and the Beatific Vision was a far greater punishment than any sensible torments of Hell, Aquinas added that these souls do not have the knowledge of what they have missed. Essentially, Aquinas leaves them in a state of ignorant bliss.  In all, Aquinas’ theological speculation was regarded as the best explanation for this problem.

The topic continued to be debated.  In the later eighteenth century, the heretical group known as the Jansenists promoted St. Augustine’s position and rejected the idea of limbo.  Responding to the declarations of a Jansenist meeting known as the Synod of Pistoia (1786), Pope Pius VI issued Auctorem Fidei (1794), a condemnation for teaching something “false, rash, and injurious to Catholic education” since they denied that there is a place “which the faithful generally designate by the name of limbo for children.”  Actually, this declaration is the only official Church docuмent containing the word limbo.  Keep in mind that the Holy Father neither defined nor rejected the teaching of limbo.  Therefore, theologians continued to investigate and to debate the matter.

In the 1940s, renewed interest arose in this area.  Using the argument of baptism by desire, some theologians speculated that God in His mercy would look favorably upon the desire for salvation of the Church, the family, the unbaptized infant, and even of Himself, and welcome the unbaptized child to Heaven.  Here again the Magisterium provided succinct guidance.  Pope Pius XII asserted that “an act of love can suffice for an adult to acquire sanctifying grace and supply for the lack of baptism; to the unborn or newly born infant, this way is not open” (Acta Apostolicae Sedis, XLIII, 84).  Later in 1958, the Holy Office (now the Sacred Congregation for the Doctrine of the Faith) admonished, “The practice has arisen in some places of delaying the conferring of Baptism for so-called reasons of convenience or of a liturgical nature– a practice favored by some opinions, lacking solid foundation, concerning the eternal salvation of infants who die without Baptism.  Therefore this Supreme Congregation, with the approval of the Holy Father, warns the faithful that infants are to be baptized as soon as possible…” (Acta L, 114).  Again, the Magisterium neither defined nor rejected the idea of limbo.

Although we do not hear of limbo much these days, the very truths surrounding the discussion stand.

 The Catechism asserts: “As regards children who have died without Baptism, the Church can only entrust them to the mercy of God, as she does in her funeral rites for them. Indeed, the great mercy of God who desires that all men should be saved, and Jesus’ tenderness toward children which caused him to say, ‘Let the children come to me, do not hinder them,’ allow us to hope that there is a way of salvation for children who have died without Baptism.  All the more urgent is the Church’s call not to prevent little children coming to Christ through the gift of holy Baptism” (#1261).

 Therefore, while we hope and pray that God who is infinitely merciful would welcome into Heaven a child who dies without the benefit of Baptism, we must not neglect our duty to baptize– the only certain way for a child to attain salvation.

https://catholicstraightanswers.com/whatever-happened-to-limbo/

"That, too"?
You are absolutely mistaken in your logic.

Abortion is wrong because it violates the fifth commandment and has nothing to do with baptism.

I never said I don't believe in Limbo.  What I said was:
"I was taught Limbo was only used before the resurrection and ascension and is now closed."

what do you believe happens to unbaptized infants?  

"That, too"?
You are absolutely mistaken in your logic.

Abortion is wrong because it violates the fifth commandment and has nothing to do with baptism.

 the child being killed before being born has no hope for salvation at all, no chance whatsoever. 

The Church has never defined dogma on such.