The woman’s child in 12:2 is Christ, the single promised seed of Abraham (Galatians 3:16). God hides the elect in him. Psalm 2 promises him the nations, and Matthew 18:3 shows that he rules now as a child.
Isaiah uses the child as a symbol, and a barren woman conceives by God’s power alone. Isaiah 9:6 names the child Wonderful, Counsellor, the mighty God, the everlasting Father, the Prince of Peace. The minister’s job is to proclaim that child, and the church confesses him.