Necrotising enterocolitis (NEC)

What is necrotising enterocolitis?

Necrotising enterocolitis (NEC) is when parts of the bowel tissue become inflamed and die. NEC may affect only the innermost lining of the bowel or the entire thickness of the bowel wall. It may also affect varying amounts of bowel.

NEC is the most common gastro-intestinal emergency in newborn babies. Around 9 in 10 babies with NEC are preterm babies (babies born before 37 weeks of pregnancy).

Babies born with a low birthweight are also more likely to get NEC. The lower the birth weight, the higher the likelihood of getting NEC.

Around 1 in 3 babies who have NEC will die from it. Of the babies that survive NEC, around 1 in 4 will have long term medical problems because of NEC.

Babies with NEC receive treatment in the neonatal intensive unit (NICU) for specialised care. You and your baby may need to transfer to a larger hospital if there is no NICU in the hospital, or birthing unit, where your baby is born.

What are the symptoms of NEC?

The symptoms of NEC can vary, but they can be divided into gastro-intestinal symptoms and more general symptoms and signs.

The gastro-intestinal symptoms include:

• abdominal distention (a swollen tummy)
• vomiting
• feeding intolerance (your baby's gut will have difficulty absorbing food)
• blood in your baby's stool

The more general symptoms include:

• temperature instability (your baby's body temperature may vary a lot)
• a low heart rate
• apnoeas (where your baby may temporarily stop breathing)
• low blood pressure
• lethargy

What are the risk factors for NEC?

There are a several risk factors for developing NEC. Prematurity is a major risk factor, although NEC can occur in term babies (babies born on time). Term babies are most likely to get NEC if they have other congenital medical problems or if they need major surgery on their heart or gut. Blood flow abnormalities to the gut caused by various health conditions can also cause NEC.

NEC is also more likely to occur in babies who have been fed and is less likely to occur in babies receiving fluids or nutrition through their veins (intravenous, or IV). Around 1 in 10 babies who develop NEC have never been fed before. Babies who are being fed formula are 6 times more likely to develop NEC than babies who are only fed breast milk.

Why do premature babies get NEC?

Premature babies have immature and delicate digestive systems (guts). This makes their gut very sensitive to changes in blood flow and to infection, and this makes them more likely to develop NEC. Doctors do not usually know why an individual baby gets NEC.

How can the risk of NEC be reduced?

Giving your baby breast milk rather than formula is a proven way to reduce the risk of NEC. If you have a low breast milk supply, or your milk is taking time to come in, you can consider using donated breast milk. Talk to your baby's doctor for more information about using donor breast milk.

Your doctor might also suggest giving you corticosteroids before the birth, since this can also help reduce the risk of your baby having NEC.

In situations where your healthcare team suspects your baby has NEC, even when the diagnosis is not completely clear, they may recommend stopping your baby's feeds and only giving fluids or nutrition through the vein — this is to help prevent progression of the condition.

How is NEC diagnosed?

To diagnose NEC, your baby's doctor will examine your baby, do blood tests and order an x-ray of your baby's abdomen (tummy). Sometimes, the diagnosis of NEC is very clear and obvious. Other times, especially if the process of NEC is just beginning, it can be more difficult to identify and diagnose.

How is NEC treated?

If your baby has NEC, their doctor will stop your baby's feeds and all oral medicines. Your baby will receive fluids or nutrition through their vein (intravenous, or IV) instead.

Your baby will also have a tube inserted into their stomach through their nose or mouth to drain air and fluids from the stomach and gut.

A sample of their blood will be taken and sent to the lab to look for infection. Your baby will also need antibiotics that can help prevent a wide range of bacterial infections.

Your baby may need to be connected to a breathing machine (ventilator) if they are very unwell, and morphine may be given to help control pain. A paediatric surgeon will examine your baby to decide if they need surgery.

Resources and support

For more information about NEC and its symptoms, diagnosis and treatment visit The Royal Women's Hospital page on NEC.

Miracle Babies Foundation has a 24-hour family support helpline, called NurtureLine 1300 622 243 (1300 MBABIES).

Read more on donor breast milk and milk banks.