Is it right that 60% of erbs palsy cases happened because of congenital problem in pelvic of the mother?

Injury of the : Brachial Plexus, 5 nerves that exit the spinal cord between neck bones & give the arm movement & feeling, can occur at delivery of a breech or large baby or if baby's head delivers normally but 1 shoulder gets stuck under mom's pelvic bones. In 90%, function recovers in 2 wks. or in 3-6 mos. with physical therapy. Seek treatments for depression/ anxiety, as they can impact infant development.