A newborn who exhibits cyanosis while quiet but turns pink when crying is likely suffering from what condition?

The condition described in the question, where a newborn experiences cyanosis while quiet but turns pink upon crying, is most indicative of choanal atresia. This congenital condition is characterized by an obstruction or closure of the back of the nasal passage, which can lead to difficulty in breathing, especially during quiet states when the infant is at rest.

When the baby cries, the increased respiratory effort can create a more open airway; thus, the cyanosis may resolve and the infant may appear pink. This pattern of cyanosis associated with respiratory distress that improves with increased airflow (i.e., when crying) supports the likelihood of choanal atresia.

In contrast, conditions like pneumothorax or congenital heart defects such as tetralogy of Fallot or transposition of the great arteries typically present with persistent cyanosis that does not improve significantly with crying. Such heart defects often lead to systemic oxygenation issues independent of the infant's activity level or respiratory effort. Therefore, the presentation aligns more clearly with choanal atresia.