Pyloric Stenosis in Babies : Causes, Symptoms, Treatment and Prevention


Pylorus is a muscular valve in the distal part of stomach which connects stomach to duodenum. It has two parts pyloric antrum and pyloric canal. It prevents regurgitation of intestinal contents into the stomach and prevent passage of large or undigested food particles into the intestine.

What is pyloric stenosis ?

In this rare condition, muscles of pylorus part of the stomach abnormally enlarges causing narrowing of the opening and thereby preventing food from entering the intestine. It mainly affects babies between birth and 6 months of age.

Pyloric Stenosis in Babies: Causes, Risk, Symptoms and Treatment

Pyloric Stenosis in Babies

What causes pyloric stenosis?

The exact reason for the thickening of the muscle is not known but it is speculated that the abrupt thickening could occur either at birth or early after birth. These conditions lead to two types of pyloric stenosis in infants:

Congenital pyloric stenosis or congenital hypertrophic pyloric

Stenosis, occurs when the baby has a thickened pyloric muscle right from the birth. Exact cause is not known but it appears to have familial clustering and recessive genetic origin.


Acquired pyloric stenosis, or acquired hypertrophic pyloric stenosis, is observed couple of weeks after birth, and is related to antral gastritis and tumours in the region(gastric carcinoma , lymphoma , pancreatic carcinoma )

What are the risk factors?

The following conditions increase the chances of a baby developing pyloric stenosis:

  • Age and gender: mainly seen in male infant , 3 to 6 weeks old. Boys are four times more likely to develop pyloric stenosis than girls.
  • Hereditary: if a parent had pyloric stenosis, then the baby has a 20% higher chance of developing the condition. It happens due to transmission of faulty and abnormal genes through generations.
  • Preterm infants or first-born baby: they have a higher incidence of pyloric stenosis though the exact reason is unknown.
  • Smoking during pregnancy: women who smoke during pregnancy are more likely to have a baby with pyloric stenosis.
  • Exposure to erythromycin: babies administered with erythromycin during the first two weeks of life are at a higher risk of developing infantile pyloric stenosis. Other high-risk cases of infants developing the condition are when mothers consume erythromycin during the last couple of weeks of pregnancy or during the first month of lactation.

What all symptoms your baby will show ?

Your baby may show following symptoms :-

  • Projectile vomiting after feeding: The baby will throw up with force, spurting the contents of the stomach in a projectile arc flow. The vomiting is so forceful that the ejected contents could land several feet away. Projectile vomiting happens a few minutes to an hour after a feed. At this stage, the baby seems in no apparent discomfort and appears quite calm. The vomit may sometimes contain blood. It may also smell sour because it comes from your baby‘s stomach, where it is been mixed with stomach acid
  • Persistent hunger:  Babies who have pyloric stenosis often want to eat soon after vomiting.
  • Stomach contractions and abdominal pain Since the pylorus is choked, the muscles use extra force to push the food. This brute thrust of the muscles is externally visible as ripples or waves around the abdominal cavity.
  •  lump in abdomen
  • Lethargy and dehydration: Your baby might cry without tears or become lethargic. You might find yourself changing fewer wet diapers or diapers that aren’t As wet as you expect, a sunken soft spot on the head, and sunken eyes.
  • Constipation and changes in bowel movements: There will be fewer soiled diapers and the excreta will only be mucus or bile that originates from the intestines
  • Weight problems: Pyloric stenosis can keep a baby from gaining weight, and sometimes can cause weight loss.
  • More fussiness

If you spot any of the other symptoms, rush the baby to a doctor right away as the condition could lead to some serious complications.

How it can be treated ?

Before starting the treatment your baby is physically examined by the doctor . Sometimes the doctor can feel the olive shaped lump and sometimes waves or ripples (due to peristalsis) can be seen in the abdomen.

Doctor might recommend blood test for checking electrolyte imbalance , x-ray or ultrasound to view thickened pylorus.


If the diagnosis is positive then your baby should be treated immediately.

Pyloric stenosis is treated in two stages. First, iv fluids and nutrients are given intravenously to treat dehydration and to maintain electrolyte balance. After this ,surgery called  pyloromyotomy is done in which the surgeon cuts open the thickened pylorus muscle that has caused the narrowing thereby allowing the passage of food from stomach to intestine. This surgery is performed using either an open or laparoscopic surgical approach..

Your baby should be able to go home a day or two later. Your baby may be given iv fluids until she begins to eat and their might be few episodes of vomiting after the surgery.

How it can be prevented ?

Usually this condition cannot be prevented. If you know about a family history of this medical condition you should pay close attention to your child and watch for symptoms. If these symptoms and signs appear, you should contact the doctor immediately. Prompt treatment will ensure that your child suffers no long term effects. Make sure to look for medical assistance as soon as possible to enable proper and timely treatment for your child.

You should avoid smoking during pregnancy and should not take erythromycin during the gestation period.

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