In which population does hypertrophic pyloric stenosis most commonly occur?

Hypertrophic pyloric stenosis is a condition characterized by the thickening of the pylorus, the muscle at the lower end of the stomach, which can lead to narrowing of the pyloric channel and obstruction of food entering the small intestine. This condition predominantly occurs in male infants, particularly in those who are first-born.

Research shows that hypertrophic pyloric stenosis affects males significantly more frequently than females, with a reported ratio of around 3:1. First-born infants, especially males, are at a higher risk, which supports the association of this condition with that specific demographic. It is thought that genetic and environmental factors may play a role in the predisposition of first-born male children, contributing to the development of this condition.

While hypertrophic pyloric stenosis can occur in females or later-born children, these scenarios are less common, which aligns with the choice indicating male infants, particularly those who are first-born, as the most affected population.