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What is necrotising enterocolitis (NEC)?

NEC is a serious medical condition where the bowel becomes inflamed and damaged. It affects babies born before 37 weeks, and babies with other medical conditions.

NEC usually only affects babies who are being treated in the neonatal intensive care unit (NICU) and are already unwell.

Babies in NICU have a 1 in 20 chance of developing NEC. This increases to 1 in 10 if they weigh less than 1.5kg (3.3lb).

Some babies with NEC will need surgery to remove damaged sections of bowel.

Sometimes NEC can be life-threatening.

7 in 10 babies with NEC will recover.

Signs of NEC

The symptoms of NEC are:

  • vomiting
  • a swollen tummy (abdomen)
  • breathing difficulties
  • blood in the poo
  • generally unwell
  • low blood pressure


The cause of NEC is not fully understood but the risk increases with:

  • underdeveloped bowels
  • low blood supply
  • bacterial infection
  • immune response

Full term babies born can develop NEC if they have low blood supply to the bowel.

The chance of developing NEC is the same whether or not a close relative has the condition.

The condition is not caused by anything the parents have done or not done during pregnancy.

The condition is not inherited and any future pregnancy is not at increased risk.

There is some evidence to show babies fed with breast milk have lower chances of developing NEC.

No medicines have been proven to prevent NEC yet.


Your baby will have blood tests and an X-ray to confirm the diagnosis.


Your baby will:

  • not be fed milk for 7 to 10 days to allow the bowels to rest
  • have a soft tube inserted into a vein in the arm, leg, or neck called a PICC line. This is used to give your baby nutrition, antibiotics, medication and for taking blood for tests.
  • have intravenous fluids (drip) so they can receive fluids and antibiotics
  • have regular blood tests and X-rays

Some babies will need an operation to remove damaged bowel.


Around 3 in 10 babies with NEC will need surgery. Usually this is because a hole has developed in their bowel.

The operation will remove the part(s) of the bowel that has been damaged and any holes are repaired.

Only specialist neonatal centres are able to carry out this type of operation. We accept babies who are transferred from other hospitals.

Some babies are too unwell to have the operation straight away so they will have a procedure to drain away infection first. A small tube will be put into the tummy under local anaesthetic at your baby’s cot. The operation will take place when your baby is less unwell.

After the operation

Your baby will return to NICU after the operation. They are likely to need help to breathe at first and will be connected to a ventilator.

Your surgeon will tell you what they found and what this means for the outlook for your baby.


The outlook for babies with NEC depends on how severe the condition is.

If your baby did not need an operation there are usually no long-term complications.

The more the bowel is damaged the more likely your baby may have:


NEC can cause scarring and narrowing (strictures) of your baby’s bowel. This can cause blockages and another operation might be needed.

Short Bowel Syndrome (SBS)

If a large section of bowel was removed there is a chance your baby may develop short bowel syndrome. This is when the bowel is not long enough to absorb all the nutrients that your baby needs to grow.

If your baby has SBS they may need:

  • artificial nutrition (total parenteral nutrition – TPN) for a long time
  • more operations
  • to stay in hospital longer

Further information about NEC

More information can be found at NEC UK: Homepage