Pulmonar causes of neonatal res irator distressRespiratory distress syndrome (hyaline membrane disease) Meconium aspiration syndrome Pneumonia Transient tachypnea of newborn Persistent pulmonary hypertension Congenital malformation —> TEF, Diaphragmatic hernia, lobar emphysema, pulmonary hypoplasia. Upper airway obustruction --> choanal atresia, vocal cord palasy, lingual thyroid.Pulmonary hemorrhageComing back to question -The newborn baby in this question is preterm neonate (born before 37 weeks). Diaphragmatic hernia may occur in term or preterm infants and may present as respiratory distress soon after birth. Hyaline membrane disease (HMD) is a disease of preterm neonates and present as respiratory distress during first 6 hours of life. Bronchopulmonary dysplasia (BPD) occurs most commonly in neonate of HMD who have been treated with oxygen and positive pressure ventilation ---> Instead of showing improvement on 3rd-4th day, some infants of HMD develop an increased need of oxygen and ventilatory support. So, BPD is not a differential diagnosis of respiratory distress at 2-3 hours after birth.