The most Blessed Virgin Mary was, from the first moment of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Saviour of the human race, preserved immune from all stain of original sin. 135
Catechism number 499
The deepening of faith in the virginal motherhood led the Church to confess Mary's real and perpetual virginity even in the act of giving birth to the Son of God made man.154 In fact, Christ's birth "did not diminish his mother's virginal integrity but sanctified it."155 and so the liturgy of the Church celebrates Mary as Aeiparthenos, the "Ever-virgin".156