Pyloric stenosis or Pylorostenosis is an uncommon condition affecting the opening between the stomach and small intestine in infants. More precisely, it is narrowing of the opening from the stomach to the first part of the small intestine known as the duodenum, due to enlargement of the muscle surrounding this opening, which spasms when the stomach empties. In pyloric stenosis, the pylorus muscles, which hold food in the stomach until it is ready for the next stage in the digestive process, thicken and therefore block food from entering the baby's small intestine. This condition causes severe projectile non-bilious vomiting. It most often occurs in the first few months of life, when it may thus be more specifically labeled as infantile hypertrophic pyloric stenosis.



The symptoms of pyloric stenosis usually appear within three to six weeks after birth, but they are rare in babies older than age 3 months. The symptoms include:

  • Projectile vomiting
  • Persistent hunger
  • Stomach contractions
  • Dehydration
  • Changes in bowel movements
  • Weight problems



The causes of pyloric stenosis are unknown, but genetic and environmental factors probably play a role.


Risk Factors

The following categories are considered to be at greater risk:

  • Male babies
  • Babies who have family members that have had this disorder
  • Babies who have been given certain antibiotics, such as erythromycin, in the first weeks of life for whooping cough have an increased risk of pyloric stenosis



Pyloric stenosis can lead to:

  • Failure to grow and develop at a normal, healthy rate;
  • Dehydration;
  • Stomach irritation;
  • Jaundice (yellowish discoloration of the skin and eyes)