Final answer:
The comment by a parent indicating that the 1-month-old 'tires out during feedings' would alert the nurse to the presence of a congenital heart defect. This particular sign is specific to heart problems due to the increased work the heart must perform during feeding.
Step-by-step explanation:
The comment made by a parent that would alert the nurse about the presence of a congenital heart defect in a 1-month-old is: b. He tires out during feedings. This is a concerning sign because infants with congenital heart defects often have difficulty feeding due to fatigue associated with the extra work their heart has to do during sucking and swallowing. The other options, such as being always hungry, being fussy for several hours every day, or sleeping all the time, although potentially concerning, are not as specifically indicative of a heart defect as the symptom of tiring easily during feedings.
It's important for healthcare providers to be aware of the signs and symptoms that suggest heart problems in infants, including difficulty feeding, which could indicate that the baby's heart might not be able to handle the increased work demand during feeding. This can lead to poor weight gain and growth, making it a critical symptom to monitor and address.