New York mothers should know that Erb's Palsy, or brachial plexus birth palsy, is a birth injury that causes the arm of a baby to grow weak and leads to loss of motion. Erb's Palsy often develops after a difficult delivery when the neck of a baby is moved to the side during a tumultuous delivery.
Infants with Erb's Palsy tend to suffer from a weakened arm during the first two years of their life. A child suffering from this condition not able to move the afflicted arm, but a physical therapist may be able to teach the parents exercises to stimulate the appendage. These therapy exercises should ideally be done when the baby is around three weeks old so that the affected arm does not become too stiff and cause contracture of the joints.