Is labor pain unbearable?
Labor pain is caused by the irritation of nerve endings due to uterine contractions, soft tissue compression during the fetal presentation, the extension of uterine ligamentous apparatus, etc.
But nature made provisions for women by setting their pain threshold much higher than that of men. Prior to childbirth, it rises even higher. The body's anti-pain system gets in the game, helping release natural anesthetics into the bloodstream.
Therefore, labor pain can't be called unbearable.