Contradiction with Isaiah 54:1
Isaiah 54:1 speaks of the barren woman being more fruitful, which contrasts with Isaiah 49:20's theme of being constrained by children due to surplus.
Isaiah 54:1: Sing, O barren, thou [that] didst not bear; break forth into singing, and cry aloud, thou [that] didst not travail with child: for more [are] the children of the desolate than the children of the married wife, saith the LORD.
Contradiction with Job 3:11-13
Job laments his birth and existence, opposite to the joy implied in Isaiah 49:20 with children crowding.
Job 3:11-13: Why died I not from the womb? [why] did I [not] give up the ghost when I came out of the belly?
Contradiction with Ecclesiastes 4:3
This verse suggests that those not yet born are better off than the living, contradicting the idea of multiple offspring being a blessing in Isaiah 49:20.
Ecclesiastes 4:3: Yea, better [is he] than both they, which hath not yet been, who hath not seen the evil work that is done under the sun.
Contradiction with Jeremiah 16:2-4
Here, having children is portrayed negatively due to impending suffering, unlike Isaiah 49:20 which implies prosperity with many offspring.
Jeremiah 16:2-4: Thou shalt not take thee a wife, neither shalt thou have sons or daughters in this place.
Contradiction with Hosea 9:11-12
These verses describe the destruction and loss of children as a curse, which contrasts with the abundance and life described in Isaiah 49:20.
Hosea 9:11-12: [As for] Ephraim, their glory shall fly away like a bird, from the birth, and from the womb, and from the conception.