Necrotizing enterocolitis (NEC) is a serious illness in newborns. It happens when tissue in the large intestine (colon) gets inflamed. This inflammation damages and kills some tissue in your baby’s colon.

Any newborn can get NEC. But it’s most common in very sick or premature babies. This is especially true for babies who weigh less than 3 pounds, 4 ounces (1,500 grams). It is rare in older, larger babies. The smaller and earlier the baby, the higher the risk for NEC. 


Doctors don't know what causes NEC. It may happen if not enough blood and oxygen reach your baby’s immature intestinal tissues. Bacteria from the environment can damage the tender tissues. This can harm the tissues and cause them to die. When this happens, a hole forms in the intestine. This can cause a severe infection in your baby’s belly (abdomen).

Risk Factors

Several things may raise your baby’s risk for NEC.

Premature birth

Premature babies are less mature than full-term babies. This means they may have trouble with blood and oxygen circulation. Their body is not always ready for digestion and fighting infections. This increases their chance of having NEC.

Formula feeding

Any premature baby is at risk for NEC, but babies who don't get human milk are more likely to get NEC.  Human milk is easier to digest. It also contains substances that help fight infection and help intestinal cells mature.

Difficult birth or low oxygen levels at birth

Babies who had a difficult birth or low oxygen levels at birth are more likely to get NEC. When there is too little oxygen, the body sends blood and oxygen to the brain and heart first. This reduces the blood flow to the intestinal tract. This can cause less oxygen in blood to reach the colon.

Infections in the intestine

Babies with infections in their intestines are more likely to get NEC.


Each child may experience symptoms differently. Symptoms usually show up in the first 2 weeks of life. They may include:

  • Bloating or swelling of the belly (abdominal distention)
  • Food doesn’t move through to the intestines
  • Greenish-colored fluid (bile) in the stomach
  • Bloody bowel movements

Signs of infection include:

  • Breathing that stops and starts (apnea)
  • Slow heart rate
  • Sluggishness (lethargy)

The symptoms of NEC may be similar to symptoms of other conditions. Make sure your child sees his or her healthcare provider for a diagnosis.


Your baby’s healthcare provider will check him or her for signs of NEC.

Your child may need an abdominal X-ray. An X-ray can show if your child’s intestine has a bubbly appearance. It can also show signs of air or gas in the large veins of your child’s liver. Air may also be on the outside of the intestines in your child’s belly (abdomen).

Your child’s healthcare provider may also put a needle into his or her abdominal cavity. This is to look for intestinal fluid in your child’s abdomen. This is a sign of a hole in the intestines.


Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is. Treatment may include:

  • Stopping feedings
  • Running a tube from your child’s nose to his or her stomach (nasogastric or NG tube). This is done to keep your child’s stomach empty.
  • Giving your baby IV (intravenous) fluids and nutrition
  • Giving antibiotics for infection
  • Taking X-rays to check how the condition is progressing
  • Giving extra oxygen or using a breathing machine. This is done if your child’s abdomen is so swollen that it interferes with breathing.
  • Isolating your baby. This is done to keep any infection from spreading.

If your baby has severe NEC, he or she may need:

  • Surgery to take out the damaged intestine or bowel
  • A procedure that connects part of the intestine or bowel to an opening on the abdomen (ostomy)
  • Draining of the abdominal (peritoneal) cavity


NEC can cause a hole to form in your baby’s intestines. This makes bacteria inside the intestinal tract leak into your child’s intestinal wall and sometimes out into the abdominal cavity. This causes an infection. This can harm a small or large part of the intestine. It can happen quickly.

An infection in the intestines is hard for a baby to fight. Even with treatment, there may be serious problems. Some of these issues include:

  • A hole in the intestine
  • Scars or narrow areas (strictures) in the intestine
  • Not being able to absorb food and nutrients. This can happen if large amounts of your child’s intestine have to be removed.
  • Severe infection affecting the entire body (sepsis)
  • Death


No one knows what causes NEC. This means that it’s hard to prevent it. Studies show that babies who only have breastmilk, instead of formula, are less likely to get this condition.  Also starting feedings after a baby is stable and slowly increasing how much he or she eats may also help.  

Key Points

  • NEC is a serious illness in very sick, usually premature newborns. It happens when tissue in the large intestine (colon) gets inflamed.
  • No one knows what causes NEC. High-risk babies, especially premature babies who are fed formula through bottles or tubes, are more likely to get it.
  • Symptoms usually show up in the first 2 weeks of your baby’s life.
  • Your child’s healthcare provider may do an abdominal X-ray to diagnose him or her.
  • Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

Next Steps

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
  • Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
  • Ask if your child’s condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if your child does not take the medicine or have the test or procedure.
  • If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.