What is necrotizing enterocolitis (NEC)?
Necrotizing enterocolitis (NEC) is a serious gastrointestinal problem that mostly affects premature babies. The condition inflames intestinal tissue, causing it to die.
A hole (perforation) may form in your baby's intestine. Bacteria can leak into the abdomen (belly) or bloodstream through the hole. NEC usually develops within two to six weeks after birth.
In some infants, NEC is mild. Others experience severe, life-threatening symptoms. You pronounce the condition nek-ruh-TIZE-ing en-ter-o-ko-LIE-tis.
What are the intestines?
The small and large intestines are part of the digestive system. The intestines help turn food and liquids into waste. Your body removes this waste through poop.
Who might get necrotizing enterocolitis?
Nearly all babies — 9 out of 10 — who get NEC are born early. The condition mostly affects babies:
How common is necrotizing enterocolitis?
In premature infants, NEC is a common gastrointestinal illness. It affects 1 in 1,000 premature babies. The risk is greatest for babies weighing less than 2 pounds.
The condition only rarely affects full-term infants. About 1 in 10,000 full-term babies get NEC.
What are the types of necrotizing enterocolitis?
Healthcare providers classify NEC into types based on when symptoms start and what causes the condition. The different types of NEC include:
- Classic: This most common type of NEC tends to affect infants born before 28 weeks of pregnancy. Classic NEC occurs three to six weeks after birth. In most instances, the baby is stable and doing well. Then the condition comes on suddenly, without warning.
- Transfusion-associated: An infant may need a blood transfusion to treat anemia (lack of red blood cells). About 1 in 3 premature babies develop NEC within three days of getting a blood transfusion.
- Atypical: Rarely, an infant develops NEC in the first week of life or before the first feeding.
- Term infant: Full-term babies who get NEC usually have a birth defect. Possible causes include congenital heart condition, gastroschisis (intestines that form outside of the body) and low oxygen levels at birth.
Although rare, NEC outbreaks can happen in neonatal intensive care units (NICUs). NICUs provide advanced medical care for premature and critically ill babies. During an outbreak, several infants can develop NEC at the same time. Bacteria, such as e. Coli, or other germs may cause these uncommon outbreaks.
Symptoms and Causes
What causes necrotizing enterocolitis?
Healthcare providers don’t know exactly what causes NEC. We do know that premature infants have weaker immune systems. The immune system helps the body fight off infections.
An infant’s digestive system is also weaker. When premature babies get an intestinal infection, their immune and digestive systems have a hard time fighting it.
Oxygen-carrying blood also has a harder time reaching the intestines in premature babies. Diminished blood flow can damage intestinal tissue. This damage allows bacteria to leave the intestines and enter the abdominal cavity or bloodstream.
What are the symptoms of necrotizing enterocolitis?
NEC typically occurs two to six weeks after birth, depending on the type and cause. Symptoms may come on over a few days or appear suddenly in babies who otherwise seem to be doing well.
NEC is a common problem among infants in NICUs. Your baby’s care team will be on the lookout for signs of this problem.
Symptoms of NEC include:
Diagnosis and Tests
How is necrotizing enterocolitis diagnosed?
Your healthcare provider will examine your baby. They check for a swollen belly and other NEC symptoms.
Your provider may also order these tests:
- Blood tests: A blood test checks for bacteria and other signs of infection.
- Fecal test: This test checks for blood in your baby’s poop. It can detect blood that isn’t visible.
- X-rays: Abdominal X-rays can show signs of NEC, including air bubbles (gas) around the intestine or abdominal cavity. Air bubbles can indicate a damaged bowel or perforation.
Management and Treatment
What are the complications of necrotizing enterocolitis?
An infant with NEC is at risk for other problems, such as:
- Abdominal infection: Some infants develop a hole in the intestinal wall. This perforation allows bacteria to enter the abdominal cavity. An infection called peritonitis can result. Peritonitis increases the risk for a life-threatening blood infection called sepsis.
- Intestinal stricture: As many as 1 in 3 babies develop intestinal strictures. A stricture narrows the intestines. This condition typically occurs a few months after a baby recovers from NEC. A narrowed intestine makes it difficult for food to pass through. Some children need surgery to open up the intestine.
- Short bowel (short gut) syndrome: If NEC destroys or damages part of the small intestine, a child may develop short bowel (short gut) syndrome. This condition makes it hard for the body to absorb fluids and nutrients (malabsorption). Children with short bowel syndrome need lifelong care to get the right nutrition to grow. Some children need tube (enteral) feedings.
- Growth failure and developmental delays: Important long-term complications are growth failure, poor neurodevelopmental outcomes and developmental delays, especially in infants who required surgery. These infants require close follow-up to monitor growth and development.
How is necrotizing enterocolitis managed or treated?
Your baby’s intestines need time to rest and heal. The first step in treating NEC is to stop tube or oral feedings. Instead, your baby receives intravenous (IV) fluids and nutrients.
Your baby may also get these treatments:
- Nasogastric tube: Your provider inserts a long, thin tube through the nose (or sometimes the mouth). The tube goes into the stomach to suction out gas and fluids.
- Antibiotics: Antibiotics help fight bacterial infections.
About 1 in 4 babies need surgery to remove dead intestinal tissue and repair a hole. Your child’s provider may perform an ostomy procedure. This surgery:
- Creates a small hole (stoma) in the child’s belly.
- Connects the large intestine to the stoma.
- Allows poop to exit the body through the stoma into a bag outside of the body.
When your baby is stronger, your provider will reattach the intestines and replace them in the abdomen.
If your child is too small (weighs less than 1 pound) or too ill for surgery, your provider may place a drain (catheter) in the abdomen. The drain lessens symptoms by removing unhealthy or infected fluids and gas. If your baby still needs surgery later, the surgery will take place when your baby is bigger and healthier.
How can I prevent necrotizing enterocolitis?
If you are at risk for preterm birth, you may get corticosteroid injections. This medication boosts the health of the developing fetus. It may lower its chances of lung and intestinal problems.
Feeding an infant breast milk may lower the risk of NEC. Some studies suggest that adding probiotics (healthy bacteria) to breastmilk or formula also helps.
Outlook / Prognosis
What is the prognosis (outlook) for people who have necrotizing enterocolitis?
An estimated 8 in 10 babies with NEC survive. Some of these babies will have long-term health problems from NEC.
What questions should I ask my doctor?
You may want to ask your healthcare provider:
- What caused my baby’s NEC?
- What type of NEC does my baby have?
- What is the best treatment for my baby?
- What are the treatment complications?
- What are the long-term effects of NEC?
- Does my baby need a special diet?
- Should I look out for signs of complications when I bring my baby home?
A note from Cleveland Clinic
It can be upsetting to see your premature baby have a setback like NEC when they seem to be doing well. Care teams in NICUs have training to spot this problem and act quickly. Some babies get better with minimal treatment. Children who need surgery often go on to lead full lives. Some children have chronic digestive problems.
- American Academy of Family Physicians. Necrotizing Enterocolitis. (https://familydoctor.org/condition/necrotizing-enterocolitis/) Accessed 6/7/2021.
- Eunice Kennedy Shriver National Institute of Child Health and Human Development. Necrotizing Enterocolitis (NEC). (https://www.nichd.nih.gov/health/topics/factsheets/nec) Accessed 6/7/2021.
- Merck Manual. Necrotizing Enterocolitis (NEC). (https://www.merckmanuals.com/home/children-s-health-issues/gastrointestinal-gi-and-liver-problems-in-newborns/necrotizing-enterocolitis-nec) Accessed 6/7/2021.
- National Organization for Rare Disorders. Necrotizing Enterocolitis. (https://rarediseases.org/rare-diseases/necrotizing-enterocolitis/) Accessed 6/7/2021.
- NEC Society. What Is NEC? (https://necsociety.org/nec-now/) Accessed 6/7/2021.
- Rich BS, Dolgin SE. Necrotizing Enterocolitis. (https://pedsinreview.aappublications.org/content/38/12/552) Pediatrics Review. 2017;38(12):552-559. Accessed 6/7/2021.
Last reviewed by a Cleveland Clinic medical professional on 05/18/2021.