Congenital hypertrophic pyloric stenosis usually presents –
The symptoms vomiting usually starts after 3 weeks of age but symptoms may develop as early as1st week of life and as late as 5 months of life. - Nelson

Congenital hypertrophic pyloric stenosis

Hypertrophic pyloric stenosis is the commonest surgical disorder of the stomach during infancy.
Pylorus is thickened and elongated and its lumen is narrowed due to hypertrophy of circular muscle fibers of pylorus.
More common in boys.
More common in infants of blood group 'B' and 'O'.
Associated congenital defects are → Tracheoesophageal fistula and hypoplasia or agenesis of inferior labial frenulum.
May be associated with Turner syndrome, Trisomy 18.
Symptoms are not present at birth.
The vomiting usually starts after 3 weeks of age.
Within 2 days after birth
Around 1 week after birth
Around 2 weeks after birth
Around 2 months after birth