Brachial Plexus Birth Injuries.

Brachial plexus birth injuries (BPBIs) are typically traction type injuries to the newborn that occur during the delivery process. Although the incidence of these injuries has overall decreased from 1.5 to around 0.9 per 1000 live births in the United States over the past 2 decades, these injuries remain common, with incidence holding fairly steady from 2008 to 2014. Shoulder dystocia is the strongest identified risk factor, imparting a 100-fold greater risk. The newborn's shoulder is caught behind the mother's pubic bone, and traction performed on the child during delivery results in injury to the brachial plexus. Other risk factors associated with BPBI include macrosomia (birthweight > 4.5 kg), heavy for gestational age infants, birth hypoxia, gestational diabetes, and forceps or vacuum-assisted delivery. Breech presentation has also been described as a risk factor in the past, but there have been more recent data that challenge this association.