Mortal sin requires grave matter, full knowledge, and full and free consent of the will. If any of those three elements are missing, a mortal sin has not been committed. Lack of full knowledge or lack of full and free consent to an objectively grave action can mitigate what would otherwise be a mortal sin to a venial sin. That is why we can say that it is always possible to determine whether an action is, in itself, inherently grave, but we cannot determine any individual’s personal culpability for committing it. Only God and that individual – perhaps working with a balanced, orthodox confessor or spiritual director – can determine an individual’s personal culpability. So, yes, it is *possible *that a particular woman, suffering from fear and anxiety, may not have committed a mortal sin by an abortion she chose to obtain.
That said, given the gravity of this particular action – which was responsible for the death of a child – such a woman should certainly take this action to the confessional for help in determining her personal level of culpability. Even if the sin was venial in her case, the Church strongly recommends the confession of venial sins and the graces obtained through sacramental confession can strengthen the woman to enable her to resist any future temptation to abort a child.
