The cause of the thickening is unknown, although genetic factors may play a role. It occurs more commonly in males than in females. Approximately 1 out of 4,000 infants is affected.
Symptoms appear several weeks after birth.
There is no known prevention. The infant may have a distended abdomen . A chemistry panel often reveals electrolyte imbalances . A barium X-ray reveals a distended stomach and narrowed pylorus. An ultrasound of abdomen may also be performed.