A 3,915-g term infant is born to a 19-year-old primi gravida. The mother has received regular prenatal care and her pregnancy is uneventful. She is negative for HIV, syphilis, and hepatitis B and is Rubella immune. She smoked marijuana during pregnancy, but denies any other substance abuse. She ruptures her membranes 14 hours before the delivery and has clear amniotic fluid.
The infant is delivered by normal spontaneous vaginal delivery, which is complicated by shoulder dystocia. Apgar scores are 5, 7, and 9 at 1, 5, and 10 minutes, respectively. Soon after delivery, the infant is noted to have subcostal retractions.
Clinical examination reveals an appropriately grown term infant who has tachypnea and subcostal retractions. Her right arm is noted to be extended and internally rotated with pronated forearm. She is also noted to have a large left-sided parieto-occipital scalp swelling. The rest of the examination is normal.