Other children, while remaining in the womb of their mothers, do not suffer, because they are only in their natural place; and if they do suffer in some slight degree, at least they are unconscious of what they feel, since they are deprived of understanding; but Jesus, while an infant, endures for nine months the darkness of that prison, endures the pain of not being able to move, and is perfectly alive to what he endures. It is for this reason that Jeremias said, A woman shall compass a man. He foretold that a woman, which was Mary, should bear enclosed in her womb, not a child indeed, but a man ; a child truly as to age ; but a perfect man as to the use of reason, since Jesus Christ was full of wisdom from the first instance in his life : whom are hid all the treasures of wisdom and knowledge. Whence St. Bernard said,"Jesus was a man while not yet as born, but in wisdom, not in age." And St. Augustine, "The unspeakably Wise was in his wisdom a speechless Infant."
--St. Alphonsus Liguori, The Incarnation, Birth and Infancy of Jesus Christ