The Catholic Church teaches that Mary was preserved from the effects of Original Sin from the very first moment of her existence. This unique privilege is called the Immaculate Conception. This has been explained in lesson 4 in the section on Original sin.

It means that the new life of sanctifying grace, which was lost by original sin and is restored to Christians through Baptism, was given direct to Mary from the first moment that she began to exist as a child in the womb of her mother.