Q. 1 How many Marian Dogmas are there is in the Catholic Church?
A. 1 The Catholic Church has proclaimed 3 Marian Dogmas during its history.
Q. 2 What are they?
A. 2 The first dogma, "Mary, the Mother of God," was proclaimed by the Council of Ephesus in AD 431.
The second dogma, the "Immaculate Conception," was proclaimed in 1854 by Pope Pius IX in Ineffabilit Deus. It proclaimed that the Virgin Mary, from the first moment of her conception, by a singular grace and privilege of almighty God and by the merits of Jesus Christ, Saviour of the human race, was preserved immune from all stain of original sin. (Catechism of the Catholic Church # 491)
The third dogma, the "Assumption of Mary," was proclaimed in 1950 by Pope Pius XII in Lumen Gentium. It proclaimed that the Immaculate Virgin, preserved free from all stain of original sin, when the course of her earthly life was finished, was taken up body and soul into heavenly glory, and exalted by the Lord as Queen over all things, so that she might be the more fully conformed to her Son, the Lord of lords and conqueror of sin and death. (Catechism of the Catholic Church # 966)
Q. 3. What about the Perpetual Virginity of Mary? Is it a dogma?
A. 3. Although the Perpetual Virginity of Mary has never been officially proclaimed as a Marian Dogma of the Catholic Church, because of its universal acceptance and continued reference to it in Papal documents throughout the history of the Catholic Church, it has come to be accepted as a fourth Marian Dogma. Consequently, it can be said that the perpetual virginity of Mary is a Catholic Dogma by virtue of the ordinary and universal Magisterium.