ABSTRACT
Hypertrophic pyloric stenosis (HPS) is the most common condition requiring surgery in the first few months of life. It is characterized by hypertrophy of the circular muscle of the pylorus, causing pyloric channel narrowing and elongation. The incidence of pyloric stenosis varies widely with geographic location, season and ethnic origin.1 The incidence has been reported to be approximately three per 1000 live births.2 There is some evidence that in recent years the incidence of pyloric stenosis has increased significantly in some parts of the UK.3-5 Boys are affected four times more often than girls.6 A recent study reported a dramatic rise in incidence among male infants but not for females, so that rates for the two sexes were 6.2 and 0.9 per 1000 infants per year.7
