Final answer:
The nurse should monitor the macrosomic infant for complications like hypoglycemia or birth injuries, ensure good feeding, and coordinate with a pediatrician. Additionally, support and counsel the mother on caring for a larger baby.
Step-by-step explanation:
The nurse's most appropriate action for a macrosomic infant weighing 4550 g (9 pounds, 6 ounces) after a forceps-assisted delivery would be to carefully monitor the newborn for any potential complications associated with macrosomia. This may include observing for signs of hypoglycemia, jaundice, or injury due to the delivery, such as brachial plexus injury or fractures. The nurse should also ensure that the baby is feeding well and monitor weight changes, as significant weight loss could be a concern. Coordinating with a pediatrician for a thorough examination and close monitoring is essential. Counseling and supporting the mother regarding care for a larger-than-average baby would also be part of the nursing care.