When Infant Vomiting Is of Concern: What You Need to Know About Pyloric Stenosis

When Infant Vomiting Is of Concern: What You Need to Know About Pyloric Stenosis

While vomiting in infants is rarely a cause for concern, forceful vomiting, a condition clinically referred to as pyloric stenosis is a condition that needs to be treated by surgery

Babies throw up and vomit fairly often and usually, this is nothing to be worried about. But occasionally, infant vomiting can be of concern. This article brings you information about a particular condition related to infant vomiting, known as Pyloric Stenosis.

Pyloric Stenosis is more commonly referred to as forceful or projectile vomiting in infants. This is a relatively uncommon condition that occurs to about two to four in 1000 babies. It hardly occurs when the baby has passed six months of age.

Asian babies are rarely ever diagnosed with projectile vomiting in infants. Dr Natalie Epton, Paediatrician and Neonatologist, SBCC Baby & Child Clinic (Mount Elizabeth Novena Specialist Centre), states that in her fifteen years of practice in Singapore she has only diagnosed expat children with this condition.

 “If your child is vomiting this wouldn’t be in your top three possible reasons” she states. Still, it’s good for mums to be in the know about this condition as ‘rarely’ doesn’t mean ‘never’. 

When an infant has this condition, food is blocked from entering the small intestine. Usually, the pylorus (muscle in the lower part of the stomach) keeps the food in the stomach until it is ready for the following step in the digestive process. When this condition occurs, the pylorus thickens and builds up to an unusually large size. This blocks food from reaching the small intestine.

Vomiting in infants is common and mums are often told not to worry about it. But if projectile vomiting in infants is left  untreated, it can lead to dehydration, weight loss and further complications.


When Infant Vomiting Is of Concern: What You Need to Know About Pyloric Stenosis

Pyloric stenosis can cause complications if left untreated.

Pyloric stenosis should not be confused with:

Possetting. Vomiting small amounts after a feed.

Reflux / Gastroesophageal Reflux Disease (GERD). When the esophageal muscle is not strong enough to keep the food down and it backs up from the stomach into the esophagus. This too calls for medical attention.

Signs and Symptoms

The symptoms typically occur within the first week weeks after the child is born. The condition is rare after three months. It hardly occurs past the child’s six-month mark.

  • Throwing up after feeds.  Projectile vomiting in infants  may start out more subtly and progress to its characteristic gushing. True to what it’s called, the vomit may go past a few feet. The condition worsens when the pylorus’ opening narrows. There may even be blood in the vomit.

  • Dehydration. The hallmark signs of dehydration include dryness in the mouth, lethargy and dry diapers. It is always important to check that the infant is producing the required number of wet diapers. You might also notice that your baby is crying loudly albeit without tears.

  • Insatiable hunger. It’s no surprise that they would require a feed soon after throwing up pretty much everything that was in their stomach. Babies with this condition usually seem extremely eager to feed right after a projectile vomiting episode.

  • Irregular bowels. Constipation or fewer bowel movements may occur as a result of food not reaching the small intestine.

  • Weight loss. Projectile vomiting in infants causes them to not be able to keep weight on, for obvious reasons. They are unable to gain weight and may even end up losing weight.

  • Wavelike contractions. As the stomach muscle is fighting hard to push the food through the pylorus, you may find a wave-like contraction across your baby’s upper abdomen. This typically occurs after a feed and prior to a vomiting episode. You may also find your baby feeling anxious and restless before throwing up.

Causes and Risk Factors.

The exact cause of projectile vomiting in infants remains at large. It is mostly speculated to be a genetically inherited condition or caused by genetic abnormalities. There are however, a number of risk factors.

  • Genetic inheritance. There have been more cases of projectile vomiting in infants whose mothers were reported to have the same condition. 

  • Race. Projectile vomiting in infants is definitely more common in Caucasians than Africa-Americans. It is  rare but not absent in Asian babies. A study done between 1972 to 1974 (Singapore Medical Journal) found that per 100,000 live births, the incidence of this occurring in Indians was the highest at 35.0 followed by 21.2 for the Chinese. The lowest incidence is of 9.7 for the Malays.

  • Smoking during pregnancy. Mothers who smoke while pregnant almost double the risks of their babies being born with this condition.


pregnant women still smoking

Smoking during pregnancy increases the unborn baby’s risk of pyloric stenosis.

  • Use of antibiotics. Babies born to mothers who were administered antibiotics in their final trimester of pregnancy have a higher chance of being diagnosed with pyloric stenosis. Similarly, newborn babies who are given antibiotics to treat certain conditions in the first few weeks of their life also face higher risks.

  • Sex. For reasons beyond explanation, this condition occurs more commonly to boys than girls. First-born males are reportedly at higher risk.

  • Allergic reactions, problems with maternal hormones and chemicals and enzymes produced by the body that are incompatible with the pylorus are also possible causes that are still being researched.


  • Malnutrition. The food does not move where it should to be digested and used by the body. Malnutrition occurs when this is left untreated.  Malnutrition can affect the child’s memory and development of motor skills and coordination. While lacking in research, there have also been links to autism and similar conditions.

  • Failure to thrive.

  • Dehydration. Projectile vomiting in infants causes dehydration, which in turn messes up their electrolytes. Electrolytes are crucial in regulating vital functions.

  • Jaundice. In some rare cases, excessive vomiting leads to jaundice. 

When to call the doctor

As long as you see the trademark projectile vomiting – vomiting as far as a few feet, it is enough reason to have your baby checked. If it is a one-off occurrence and your baby is otherwise healthy and thriving you might not need to worry.

In addition to the vomiting, if your baby comes across as unusually irritable, is not as cheerful and active as usual, starts losing weight or is unable to gain weight and produces less wet diapers, make an appointment with your pediatrician.

Do note that some of the above mentioned symptoms may be totally unrelated to pyloric stenosis. In any case, unusual behaviour warrants a check for your baby. I’m sure as mums we would rather err on the side of caution.

 Tests and Diagnosis

When Infant Vomiting Is of Concern: What You Need to Know About Pyloric Stenosis

Asian doctor examining a girl by stethoscope ,mother standing beside her daughter at hospital

  • Questions and physical examination. As a common first-step, your doctor is likely to ask you questions about your baby’s symptoms and then perform a simple physical examination to check for the wave-like contractions that your baby might be experiencing. He may also look out for a lump that signals the existence of the enlarged pyloric muscle.

  • Ultrasound. An ultrasound of your baby’s belly is usually ordered as well. Just like during your pregnancy, sound waves will give the doctors a picture of what’s going on in your baby’s tummy. You can be rest assured that this is non-invasive and completely painless.

  • X-ray. In some cases, if the ultrasound fails to provide a clear picture, an x-ray, or even a Barium X-ray may be called for. Your baby will be given a chalky solution containing Barium to provide a clearer picture of her pylorus during the x-ray.

  • Blood Tests. Blood tests may also be necessary to determine if your baby’s electrolyte levels are healthy and to check for dehydration.

Treatment and drugs.

If your baby is found to exhibit signs of dehydration, she is first hooked up on an intravenous (IV) tube to get the necessary fluids and nutrients back into her system.

If diagnosed with pyloric stenosis, surgery is usually the recommended option. This process is called pyloromyotomy.

While the thought of putting an infant through surgery is incredibly daunting to all mums, if it makes you feel any better, the surgery is minimally invasive and is done by a laparoscope (a thin viewing instrument).

This is inserted through a small cut near the baby’s navel. The cut is only made on the outer layer of the enlarged pylorus muscle. The surgery then widens the opening between the stomach and the small intestine.

After the surgery, your baby will still require IV fluids until she is able to feed again. You should be given the green light to resume feeding within twelve to 24 hours.

As compared to the usual surgeries, surgeries done with a laparoscope has a faster recovery time and a smaller scar. As with any surgery, there are risks of bleeding and infection but it is unlikely. There are rarely complications with this procedure. Almost all babies recover fully and are sent home by two days or so.

It is not uncommon for babies to have a few more throwing up episodes following the surgery so be prepared for that. However, if your baby continues throwing up after a few days, do go back for a review. About one to two percent of babies require a second surgery.

There you go mums, all you need to know about that vile, malicious projectile vomiting in infants, otherwise known as pyloric stenosis.

It is unlikely that you come across someone here in Singapore who went through this ordeal. But as mums, it is important for us to equip ourselves with as much knowledge as possible about as much as possible as this helps us become more confident mums.

Trust your instincts. Doing so does not mean you are paranoid.Even if everyone from your confinement nanny to your mother-in-law tells you that it’s normal, but you feel strongly that something is amiss, it never hurts to get your child checked!

References: http://www.webmd.com/parenting/baby/tc/pyloric-stenosis-topic-overview

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Written by

Nasreen Majid

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