Which of the following is a sign of hypoglycemia in a newborn?

Hypoglycemia in a newborn can manifest through a variety of symptoms, and one of the key indicators is physiological distress, which includes both apnea and pallor. Apnea refers to pauses in breathing that can occur due to inadequate glucose levels affecting the baby's overall metabolic function. Pallor, or unusual paleness of the skin, can be a sign of poor perfusion or stress in the infant, which can also be linked to low blood sugar levels.

The presence of apnea and pallor indicates that the newborn may be struggling to maintain adequate oxygen levels and proper circulation, both of which are critical in the setting of hypoglycemia. This symptomatology highlights the urgent nature of monitoring glucose levels in newborns, particularly those at risk for hypoglycemia, such as those with a low birth weight, maternal diabetes, or those requiring intensive care post-delivery.

The other options presented do not reflect signs associated with hypoglycemia. A strong cry and good feeding would typically indicate a well-adjusted baby, while warm temperature and active movement suggest that the newborn is stable and thriving. Normal feeding habits denote a healthy feeding routine, which would be contrary to the signs of hypoglycemia.