Signs of Pyloric Stenosis in Babies
The short answer
Pyloric stenosis is a rare condition (affecting about 3 in 1,000 babies) where the stomach outlet thickens, blocking food from entering the small intestine. The hallmark sign is forceful, projectile vomiting after feeds starting around 3-5 weeks of age, with baby seeming hungry immediately after. It requires surgical correction but has an excellent prognosis when treated.
Thousands of parents search for this exact thing. You are not alone.
By Age
What to expect by age
0-2 weeks
Pyloric stenosis symptoms rarely appear in the first two weeks of life. If your newborn is vomiting, it's more likely to be normal spit-up, reflux, or feeding issues like overfeeding or swallowing air. However, if you notice true projectile vomiting (shooting several feet) at this age, contact your pediatrician promptly.
3-5 weeks
This is the most common age for pyloric stenosis to appear. Symptoms typically start gradually: first occasional vomiting after feeds, then becoming more frequent and forceful. The vomiting is projectile (shoots out with force, not just dribbling), happens shortly after most feeds, and doesn't contain bile (it's usually just milk). Baby seems hungry and eager to feed again right after vomiting.
6-12 weeks
While less common, pyloric stenosis can develop up to 3 months of age. If your older baby suddenly develops forceful, projectile vomiting after a period of normal feeding, don't dismiss it. Other signs at this age include fewer wet diapers, weight loss or poor weight gain, constipation (small, infrequent stools), and appearing dehydrated. Sometimes you can see wave-like contractions across baby's belly after feeding.
3+ months
Pyloric stenosis is extremely rare after 3 months. If your baby has projectile vomiting at this age, other causes are more likely, such as gastroenteritis, food intolerance, or reflux. Still, any pattern of forceful vomiting deserves medical evaluation.
What Should You Do?
When to take action
- Occasional spit-up that dribbles out, even if it seems like a lot
- Vomiting once or twice that doesn't create a pattern
- Baby continues to gain weight appropriately
- Plenty of wet diapers (6+ per day)
- Baby seems content between feeds
- Vomiting is becoming more frequent or more forceful
- Baby seems hungrier than usual despite feeding well
- You're concerned about the force or frequency of vomiting
- Slightly fewer wet diapers than usual
- Projectile vomiting after most or all feeds
- Baby isn't gaining weight or is losing weight
- Fewer than 4-6 wet diapers in 24 hours
- Baby seems lethargic, has sunken soft spot, or dry mouth
- You can see wave-like movements across baby's belly after feeding
- Vomit is green, yellow, or contains blood
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Digestive Concerns
My Baby's Belly Looks Swollen
A rounded, slightly protruding belly is completely normal in babies and toddlers due to immature abdominal muscles and their proportionally larger organs. However, if the belly becomes suddenly swollen, feels hard and tight, or is accompanied by pain, vomiting, or changes in bowel movements, it needs medical evaluation as it could signal gas buildup, constipation, or rarely, something more serious.
My Baby Has an Anal Fissure (Blood When Pooping)
A small streak of bright red blood on the surface of your baby's stool or on the diaper is most commonly caused by an anal fissure, which is a tiny tear in the skin around the anus from passing hard stool. Anal fissures are very common in babies and toddlers and usually heal on their own with simple measures like keeping stools soft. While this is rarely serious, any blood in your baby's stool should be mentioned to your pediatrician.
Tummy Massage for Baby Gas
Gentle abdominal massage can help relieve gas and discomfort in babies by encouraging gas to move through the intestines. The technique involves gentle clockwise circular motions on the belly (following the direction of the digestive tract), the "I Love U" stroke pattern, and gentle knee-to-tummy movements. Massage also provides comforting touch that can soothe a fussy baby.
Silent Reflux in Baby
Silent reflux occurs when stomach acid rises into the esophagus and throat but is swallowed back down rather than spit up. Babies with silent reflux may be fussy during or after feeds, arch their back, have hoarse crying, or refuse to eat, but without visible spitting up. It can be harder to diagnose than typical reflux because there is no obvious spit-up.
Bicycle Legs Technique for Gas
Bicycle legs is a simple, effective technique for helping babies pass trapped gas. Gently moving your baby's legs in a cycling motion pushes against the abdomen and helps gas move through the intestines. Combined with gentle belly massage and tummy time, it is one of the best non-medical approaches to gas relief in infants.
Dark Blood in Baby's Stool
Dark or black blood in stool (melena) is different from bright red blood and may indicate bleeding from the upper digestive tract (stomach or upper intestine). In newborns, black stools in the first few days (meconium) are normal. Beyond the first week, dark, tarry, or coffee-ground-like material in stool needs prompt medical evaluation. Some dark-colored foods and iron supplements can also darken stools without being blood.