Pyloric stenosis in babies: signs and evaluation

What does the evidence show for pyloric stenosis in babies?

• The pylorus connects the stomach to the small intestine. When its muscle becomes abnormally thick, feeds cannot pass through normally. Repeated forceful vomiting, ongoing hunger, fewer wet diapers, or poor weight gain can be clues that need pediatric evaluation. 1
• Pyloric stenosis often becomes apparent in the first several weeks after birth. Its usual vomit does not contain bile. That pattern is a clue for clinicians, not a home exclusion rule: green vomit raises concern for other urgent intestinal problems. 2
• Ultrasound is commonly used to examine the stomach outlet. The clinical team also assesses hydration and may check blood electrolytes. A caregiver does not need to find a lump in the abdomen before asking for evaluation. 1
• Reflux warning signs overlap with other feeding disorders. Repeated projectile vomiting should not simply be labeled GERD or managed through serial formula changes without an assessment, particularly when feeding or growth is deteriorating. 3
• Fever is a separate warning sign in a young infant. A rectal temperature at or above 100.4°F (38°C) before three months needs immediate medical advice, even if a feeding problem already seems to explain the vomiting. 4
• Hospital care includes correcting dehydration and electrolyte disturbances before an operation when needed. Pyloromyotomy opens the tight muscle at the stomach outlet. The surgical team directs the feeding restart and follow-up rather than a fixed home schedule. 2

Questions to discuss with your care team

When should I call my provider about pyloric stenosis in babies?

Repeated forceful vomiting with reduced urine, weight concerns, or inability to retain feeds needs prompt assessment.,Green vomit or blood needs urgent evaluation for intestinal or other illness.,Fever at or above 100.4°F (38°C) rectally before three months needs immediate medical advice.,Breathing difficulty, blue color, or a baby who cannot be awakened: call 911. Whatever the pattern, any symptom that feels beyond your usual range is a reason to call: obstetric teams expect these questions and would rather hear early than late.