This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'Congenital hyperophic pyloric stenosis is characterized by progressive gastric outlet obstruction. Incidence of congenital hyperophic pyloric stenosis is highest in: \nSelect and explain. \nA. First female baby, B. First male baby, C. Second male baby, D. Second female baby', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hyperophic pyloric stenosis (HPS) is postnatal muscular hyperophy of the pylorus. HPS occurs in approximately 1-8 per 1000 bihs and originally was believed to occur in first-born males between 3 and 6 weeks of age. Infants with HPS present with nonbilious vomiting that becomes increasingly projectile over the course of several days to weeks. Eventually, the infant develops almost complete gastric outlet obstruction. Infants with HPS develop a hypochloremic, hypokalemic metabolic alkalosis. Ramstedt pyloromyotomy is the treatment of choice and consists of incision down to the mucosa along the pyloric length. Ref: Sundaram S.S., Hoffenberg E.J., Kramer R.E., Sondheimer J.M., Furuta G.T. (2012). Chapter 21. Gastrointestinal Tract. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.', 'role': 'assistant'}]