Diagnosis

Your baby's doctor will start with a physical examination. Sometimes, the doctor can feel an olive-shaped lump — the enlarged pylorus muscles — when examining the baby's abdomen. Wavelike contractions (peristalsis) may sometimes be visible when examining the baby's abdomen, often before the baby starts vomiting.

Your doctor might also recommend:

• Blood tests to check for dehydration or electrolyte imbalance or both
• Ultrasound to view the pylorus and confirm a diagnosis of pyloric stenosis
• X-rays of your baby's digestive system, if results of the ultrasound aren't clear