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Necrotising Enterocolitis

(Symptoms, Causes, diagnosis & Treatment )

Symptoms and signs of NEC

The signs & symptoms of NEC vary between babies and it is important to realise that you may see these signs in babies who do not have NEC. Doctors and nurses often look for signs & symptoms including:

  • Abdominal pain, tenderness or discomfort

  • Swollen or distended tummy

  • Abdominal discolouration 

  • Blood in the stool

  • Diarrhoea

  • Vomit or aspirates containing blood or bile

  • Apnoea (prolonged pauses in breathing)

  • High, low or unstable temperature

  • Tiredness or lethargy


Radford 2016

Causes of NEC

In most cases we do not know why NEC happens. The word NEC means two things; firstly 'enterocolitis' means inflammation of the lining of the bowel. Secondly, 'necrotising' means damage/death of tissue. Not all cases involve permanent damage (necrosis) to the bowel; sometimes there is inflammation that does not continue to get worse.


NEC is most common in premature infants, but also occurs in full term babies with other problems such as heart disease. Premature babies have immature body organs and immune systems. This means babies may have problems digesting and absorbing milk, or problems with oxygen levels and blood circulation. Premature babies also have under-developed immune systems meaning they are more at risk of infections. In full term babies, low oxygen levels at delivery, or because of heart or gut problems may be a factor, and most cases of NEC occur in the first week or two. However, in premature babies, most cases of NEC happen in the second and third weeks of life when oxygen levels are more stable. 

Even though doctors do not know exactly why NEC happens, it appears to be related to the the following 1) the type and amount of milk feeding - it is much less common in babies who receive their own mothers' milk 2) the types of bacteria that live in the gut; and 3) damage or inflammation to the lining of the gut - this may be more common where blood or oxygen supply is less good.



Doctors make a diagnosis of 'suspected NEC' by 1) looking at what is happening with milk feeds, aspirates, passing poo etc. 2) doing a physical examination to see if the abdomen is full or tender and 3) running various tests. It is common to do an abdominal X-ray looking to see if the bowels look widened (distended) or obstructed. Sometimes there are clear signs of NEC (e.g. a perforation) but often the X-ray is 'inconclusive' - this means the doctors cannot for certain if things are normal, or if there is a problem. Doctors will often do blood tests to look at the white cells (which fight infection) or platelet levels (which help the blood clot). It is common to measure something called CRP (C-reactive protein) in the blood. This may be high if there is NEC or infection, but sometimes the levels are normal.


Treatment for NEC depends on how sick the baby is and every case is different. It is very common for infants to need extra help with breathing, blood pressure, fluids and some can quickly become very poorly. 

Medical Treatment

About half of the babies with serious NEC require an operation, but many do not. Doctors will 'rest the bowel' by stopping milk feeds and using an nasogastric tube to keep the stomach empty. Babies can get all the fluid and nutrients they need through a vein (intravenous treatment or 'drip'). Doctors will also give 2 to 3 different antibiotics intravenously to treat any infection that may be present. 

Surgical Treatment

In severe cases, or if there is a perforation, then an operation under a general anaesthetic will be needed to remove the damaged sections of intestine. It is not possible to know before the operation exactly what the surgeon will need to do. It is very common for babies to have a 'stoma' after the operation. Stoma simply means opening of the bowel (see our separate section on this). The stoma allows faeces (poo) to pass out where it is collected in a bag. 

Throughout the course of treatment, babies are monitored closely and many will have further X-rays and blood tests. Unfortunately, babies can become seriously unwell very quickly, or continue to get worse after treatment is started, and some babies die from their disease. 



Many babies recover and do not have further problems, however a number of other issues or problems may develop. These include:

  • About 10-20% of babies have a further episode of NEC

  • The wound from surgery may become infected or take a long time to heal

  • The bowel getting narrow due to scar tissue forming 'strictures' - these may need an operation but this is much less risky than an operation for NEC

  • Developing short bowel syndrome due to a large portion of their bowel being removed. Babies with short bowel syndrome may develop problems absorbing food, this can affect how your baby grows.

  • Continuing to need nutrients intravenously (through their vein


NEC is a very variable conditions and no two babies are the same. The precise management plan and length of treatment is difficult to know. If you do not understand what is happening ask to speak to one of the doctors. Things you might want to ask:

  • If you baby needed an operation, the surgeon can tell you what the bowel looked like, and how much bowel was removed.

  • If your baby has a stoma, what part of the bowel is it in, for example is it 'high up' in the early part of the small intestine (jejunum), or 'lower down' towards the end of the small intestine (ileum) or in the large bowel (colon). 

  • The results of the blood tests and when the doctors plan to repeat them

  • How long the doctors think your baby needs to stay without milk ('nil by mouth') and how long they antibiotics will be needed

Please visit our Family Stories tab to read about some of the families affected by NEC. 

Information Disclaimer: The information provided by NEC UK should not be used for the diagnosis or treatment of any medical condition. Always seek medical advice from a trained & licensed physician if you have any concerns!

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