Your baby's health care provider will start with a physical examination. Sometimes, the provider can feel an olive-shaped lump when examining the baby's belly. This lump is the enlarged pylorus muscles. Wavelike contractions may sometimes be visible when examining the baby's belly, often before the baby starts vomiting.

Your provider also might 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.

More Information


Surgery is needed to treat pyloric stenosis. The procedure, called a pyloromyotomy, is often scheduled on the same day as the diagnosis. If your baby is dehydrated or has an electrolyte imbalance, your baby receives fluids [fluid replacement] before surgery.

In pyloromyotomy, the surgeon cuts only through the outside layer of the thickened pylorus muscle, allowing the inner lining to bulge out. This opens a channel for food to pass through to the small intestine.

Pyloromyotomy is often done using minimally invasive surgery. A slender viewing instrument, called a laparoscope, is inserted through a small incision near the baby's navel. Recovery from a laparoscopic procedure is usually quicker than recovery from traditional surgery. This method also leaves a smaller scar.

After surgery:

  • Your baby might be given intravenous fluids for a few hours. You can start feeding your baby again within 12 to 24 hours.
  • Your baby might want to feed more often.
  • Some vomiting may continue for a few days.

Possible complications from pyloric stenosis surgery include bleeding and infection. However, complications aren't common, and the results of surgery are generally excellent.

Preparing for your appointment

You may be referred to a health care provider who specializes in treating digestive disorders, called a gastroenterologist. Or you may be referred to a pediatric surgeon.

What you can do

  • Write down your baby's symptoms, including when and how often your baby vomits, whether the vomit is forcefully projected, and if the vomit appears to be most or just part what the baby has eaten.
  • Write down questions to ask your health care provider.

Questions to ask your doctor

  • What's the most likely cause of my baby's symptoms?
  • What tests does my baby need? Do they require any special preparation?
  • What treatments are available? Does my baby need surgery?
  • Will there be any feeding restrictions after surgery?

In addition to the questions that you've prepared, don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your provider is likely to ask you a few questions. Being ready to answer them may leave time to go over points you want to spend more time on. You may be asked:

  • When did your baby first begin experiencing symptoms?
  • Are the symptoms continuous or occasional? Do they occur only after eating?
  • Does your baby seem hungry after vomiting?
  • Does the vomit come out forcefully?
  • Does your baby have four or more wet diapers a day?
  • Is there blood in your baby's stool?
  • What was your baby's last recorded weight?
Dec. 02, 2022
  1. Kliegman RM, et al. Pyloric stenosis and other congenital anomalies of the stomach. In: Nelson Textbook of Pediatrics. 21st ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Oct. 19, 2020.
  2. Olive AP, et al. Infantile hypertrophic pyloric stenosis. https://www.uptodate.com/contents/search. Accessed Oct. 19, 2020.
  3. Danko ME, et al. Current management of pyloric stenosis. Seminars in Pediatric Surgery. 2022; doi:10.1016/j.sempedsurg.2022.151145.
  4. Hypertrophic pyloric stenosis. Merck Manual Professional Version. https://www.merckmanuals.com/professional/pediatrics/gastrointestinal-disorders-in-neonates-and-infants/hypertrophic-pyloric-stenosis. Accessed Oct. 19, 2020.
  5. AskMayoExpert. Suspected pyloric stenosis (pediatric). Mayo Clinic; 2019.
  6. Pyloric stenosis. American Pediatric Surgical Association. https://eapsa.org/parents/learn-about-a-condition/f-o/hypertrophic-pyloric-stenosis/. Accessed Oct. 19, 2020.
  7. Kashyap PC (expert opinion). Mayo Clinic. Oct. 19, 2020.


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