This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
[{'content': 'Vomiting on the 1st day of baby&;s life may be caused by all of the following \nSelect and explain. \nA. Pyloric stenosis, B. Oesophageal atresia, C. Aerophagy, D. Amniotic gastritis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The most common causes of vomiting in the neonatal period include gastroenteritis, malrotation, pyloric stenosis, TEF and necrotizing enterocolitis. In infancy, common causes are GERD, gastroenteritis, bowel obstruction, milk protein allergy and UTI. Reference: GHAI Essential pediatrics, 8th edition', 'role': 'assistant'}]