Controversies surrounding the causes of brachial plexus injury.

In the past decades, obstetric personnel have attempted to reduce the frequency of brachial plexus injury (BPI) by attempting to use less traction during the delivery of the fetal anterior shoulder. Clearly, these attempts have been unsuccessful in preventing or reducing the frequency of BPI. We conducted a nonsystematic literature review of the reported controversies regarding the mechanisms of BPI causation and why this complication is not decreasing in frequency. The review indicates that maternal labor forces are the most likely cause of BPI.