A newborn is delivered vaginally after a prolonged second stage of labor with the use of forceps. Upon assessment, the nurse notes weak movement of the left arm, absent Moro reflex on that side, and intact grasp reflex. Which birth injury should the nurse suspect?

A. The combination of weak arm movement, absent Moro reflex, and intact grasp reflex directly points to an upper brachial plexus injury, consistent with Erb’s palsy. Immediate management includes supportive care, gentle range-of-motion exercises, and referral to a pediatric neurologist or physical therapist. Early intervention improves functional outcomes and reduces long-term disability. B. Caput succedaneum is diffuse edema of the scalp caused by pressure during delivery, often crossing suture lines. It is benign, self-limiting, and does not affect limb movement or reflexes. The infant’s motor deficits are not explained by caput succedaneum. C. Cephalohematoma is a localized subperiosteal blood collection, typically limited by suture lines. It presents as a firm scalp swelling, sometimes with jaundice as a complication. Cephalohematoma does not cause limb weakness or absent reflexes, so it is inconsistent with the findings in this case. D. Facial nerve injury during birth, often due to traction or forceps application on the face, manifests as facial asymmetry, inability to close the eyelid, drooping of the mouth, or absent nasolabial fold. It does not affect arm movement or the Moro reflex, so it cannot account for the infant’s symptoms.