What Causes Brachial Plexus Palsy at Birth?
During childbirth, the shoulders may be pulled downward as the baby squeezes through the birth canal. When this happens, the brachial plexus nerves may stretch and be damaged. In some cases, the nerves may even tear. Larger birthweight babies are at a higher risk of brachial plexus palsy because it is harder for them to pass through the birth canal.