Who Is At Risk for NEC?

The most important risk factor for NEC is prematurity. Infants who are born prematurely, before 37 weeks, are automatically at an increased risk for the disease, and the earliest infants are at the greatest risk.

In addition, studies have suggested that those premature infants who are fed infant formula (as opposed to breast milk) are at an increased risk for the condition. Certain genetic factors may also play a role, though we need more research on these to determine how influential they may be.

Other risk factors for NEC include:

• Low birth weight
• Small for gestational age
• Low gestational age
• Assisted ventilation
• Premature rupture of membranes
• Black ethnicity
• Hypotension (low blood pressure)
• Difficult birth
• Low oxygen levels at birth

Why Are Preterm Infants at Risk for NEC?

Scientists aren’t yet sure of all the reasons premature infants may be more at risk for NEC. Studies have suggested that multiple factors can play a role, and it’s unclear at this point which is the most important.

We do know that premature infants have immature gastrointestinal tracts that are particularly vulnerable to infection and damage. They simply cannot protect themselves as well as infants born full-term.

This may be why the use of infant formula increases the risk of NEC. In a 2012 animal study, researchers found that infant formula, but not fresh breast milk, contains levels of free fatty acids (FFAs) that can be toxic to intestinal cells. When subjects digested preterm infant formula, it caused significant death of certain types of cells in the gut.

In a 2010 study, researchers compared intestinal cells exposed to breastmilk to intestinal cells exposed to infant formula. They found that the formula significantly increased oxidation, cell damage, and cell death.

Can Full-Term Babies Get NEC?

Full-term babies can get NEC, but it’s much less likely than it is in premature or very low birth weight infants.

Scientists have been keeping track of this. In a 2004 study, they reviewed medical charts for all full-term infants that were born at one hospital between January 1, 1998, and December 31, 2002. They found that during that five-year period, only 14 full-term infants developed NEC. All of them were delivered by C-section, and all of them were fed either a mixture of breast milk and formula or entirely by formula. All of them recovered, and only one required surgery. 

In a later study, researchers found that among the 217 infants diagnosed with NEC at their hospital, 27 (12.4 percent) were full-term neonates. The overall survival rate was 88.8 percent. The scientists concluded that NEC in full-term infants is “a rare pathology.

Is NEC an Infection?

A variety of reports describe bacterial, viral, and fungal infections that occur in association with NEC. No single organism, however, has emerged as the one to blame.

Scientists also report that bacteria alone are unlikely to cause the disease. There must be other factors present, such as an immature intestinal system (such as that which exists in premature infants) that is unable to fight off infectious agents.

The fact that treatment with antibiotics remains a mainstay of clinical management of the disease also shows that bacteria are involved.

What Bacteria Cause Necrotizing Enterocolitis?

A variety of bacterial organisms have been identified in infants with NEC. Any of them may be a factor in the disease. These include:

• Enterobacteriaceae
• Staphylococci
• Candida
• coli
• Pseudomonas
• Clostridia
• Cranobacter
• Klebsiella

Viral and fungal infections may also be associated with NEC.

What Does Enterocolitis Mean?

Enterocolitis is an inflammation that occurs in the digestive tract. The word “enteritis” refers to an inflammation of the small intestine, while “colitis” refers to inflammation of the large intestine (colon). NEC can affect both.

What is Enterocolitis and Its Treatment?

As noted above, enterocolitis is an inflammation that occurs in the digestive tract. Treatment varies depending on the severity of the inflammation, but usually involves changes in feeding, antibiotics, and other medications that may help reduce the inflammation. In severe cases, surgery may be required to remove damaged areas of the bowel.

What is Infectious Enterocolitis?

Infectious enterocolitis is intestinal inflammation accompanied by an infection. Most often, this is a bacterial infection, but it may also be a viral or fungal infection.

Can a Baby Get NEC Twice?

Though it is rare, recurrent NEC is possible. Estimates are that it happens in only 4-6 percent of patients with the disease. So far, scientists have been able to determine no reason for recurrence.

If NEC does come back, doctors will treat the baby again with feeding adjustments and antibiotics, and perhaps with surgery if necessary.

Can NEC Come Back?

As noted above, NEC may recur, but it is extremely rare.

Can a Baby Recover from NEC?

Studies indicate that NEC continues to be one of the leading causes of illness and death among preterm infants. Estimates are that 15-40 percent of infants with NEC die from the disease. Survival depends on a multitude of factors, including the severity of the disease, the infant’s birth weight, and whether the baby is fed infant formula.

Survival rates have improved over the past few decades. According to a 2019 study, rates improved from 1976-2016 even as the number of babies born prematurely increased.

Can a Baby Survive NEC?

Though NEC is a very serious disorder that can cause death, babies often survive under the right circumstances.

Standard treatment for the disease involves tube feeding, antibiotics, and consistent monitoring. If the baby has signs of severe intestinal injury, surgery may be required to remove the damaged portion of the intestine.

With improved supportive intensive care, the odds that a baby will survive today are greater than they were even a few years ago.

Is NEC Curable?

Yes. As noted above, with the right treatment, NEC can be cured and babies can go on to live normal lives. In more severe cases, the disease may cause long-term health problems.

Is NEC Genetic?

Some studies have suggested that genes may play a role when it comes to NEC. Studies of twins, for instance, suggest that genetic factors may account for up to 50 percent increased risk for NEC.

In a 2018 study, researchers discovered that one genetic variation in the region of chromosome 8 was associated with an increased risk for NEC. In another study that same year, researchers reported that several potential genetic factors for NEC in premature infants have been identified.

This is a new area of research, and we need many more studies to understand how genetics may be related to NEC.

Can Adults Get NEC?

Though NEC primarily affects premature infants of low birth weight, it can also affect adults in extremely rare cases. Scientists aren’t sure why it may occur in adults, but they believe that similar bacterial agents are involved. These may include E. coli, Staphylococcus, Clostridia, and other similar microorganisms.

Whatever may cause NEC in adults, scientists believe it must be different than what causes it in infants. Premature babies have immature intestines that are unable to defend themselves against dangerous bacteria that can cause NEC. Adults may be more likely to have some sort of vascular problem first—one that limits blood flow to the intestines, resulting in bacterial buildup.

So far, studies have indicated that adult patients who develop NEC had similar habits. They:

• were smokers
• regularly consumed alcohol
• frequented eating from unhygienic places
• had poor nutritional status
• had a lower economical status

Can Breastmilk Cause NEC?

Babies fed breastmilk can develop NEC, but their risk is lower than babies who are fed infant formula.

Several studies have found this to be true. In 2016, for instance, researchers reported that infants who were exclusively formula-fed or received a mixed diet (both formula and breast milk) were at a higher risk of developing NEC compared with breastfed infants.

Indeed, breast milk seems to be protective against NEC. In the same study, researchers found that breastmilk dramatically reduced inflammation related to NEC, protecting the bowel and reducing the risk of the disease.

About 10 percent of infants weighing less than 3 pounds, 5 ounces experience NEC. The immature bowels of these infants are sensitive and prone to infection. They may also have difficulty with their circulation and digestion, which can increase the risk of infection and inflammation.

Can Formula Cause NEC?

Though it is unclear whether formula can cause NEC, several studies have shown that it can increase a baby’s risk of developing the disease.

In a recent 2020 study, for instance, researchers found that among extremely low birth weight infants, not being fed predominantly human milk was associated with an increased risk of NEC. The researchers concluded that supporting milk production in mothers with premature infants may help prevent infant deaths.

Scientists admit that multiple factors can contribute to NEC and that the exact cause is not fully understood. But in a 2017 study, they add: “Several studies have indicated that bovine milk-based infant formulas lead to a higher incidence of NEC in preterm infants than does human milk.”

Does Formula Increase the Risk of NEC?

Several scientific studies have indicated that premature babies fed infant formula have an increased risk of NEC. The connection has become so strong that in a 2014 study, researchers wrote: “While the pathogenesis of NEC remains incompletely understood, it is well established that the risk of disease is increased by the administration of infant formula and decreased by the administration of breast milk.”

What Formula Causes NEC?

Any infant formula can increase the risk of NEC when given to a premature or low-birth-weight infant. Some of the common ones that are often used in hospital settings include Similac and Enfamil. But the brand doesn’t matter—formulas based on cow’s milk have been found in studies to increase the risk of NEC in premature babies.

Can NEC Be Prevented?

Doctors and scientists have identified several factors that may reduce the risk of NEC in infants. These include:

• Breast milk feeding
• Restrictive use of antibiotics
• Supplementation with probiotics
• Fluid restriction

Other interventions that show promise include treatment with erythropoietin (EPO), which stimulates the production of red blood cells, and lactoferrin, a protein found naturally in human and cow’s milk.

How Do You Prevent NEC in Preemies?

It is not always possible to prevent NEC, but the steps listed in the answer above will help reduce the risk.

Can NEC Cause Death?

NEC can be fatal in some cases. Certain factors can increase the risk that a baby will die from NEC. When researchers compared over 5,500 babies with NEC who survived with 1,505 that died, they found that the factors associated with death included:

• Lower estimated gestational age
• Lower birth weight
• Treatment with assisted ventilation on the day of diagnosis of NEC
• Treatment with vasopressors at the time of diagnosis

Patients who received only ampicillin and gentamicin (antibiotics) on the day of diagnosis were less likely to die. Simply put, less mature infants (born earlier), have a lower birth weight, and a more severe form of NEC are more likely to die of it.

Is Necrotizing Enterocolitis Fatal?

Necrotizing enterocolitis (NEC) can be fatal in some cases, as noted above.

What is the Survival Rate for NEC?

The mortality rate in NEC ranges from 10-50 percent in infants who weigh less than 1500 grams, depending on the severity of the disease. That means the survival rate ranges from 50-90 percent.

The mortality rate is 0-20 percent for babies who weigh more than 2500 grams. Extremely premature infants (1000 grams) are particularly vulnerable to the condition, with mortality rates of 40-100 percent.

How Do I Know if My Baby Has Necrotizing Enterocolitis?

Babies with necrotizing enterocolitis (NEC) may show the following symptoms:

• Difficulty feeding; poor tolerance to feeding
• A swollen, red, or tender belly
• Pain when someone touches the abdomen
• Diarrhea and/or dark and blood stools
• Constipation
• Being less active or lethargic
• Green vomit (containing bile)
• A low or unstable body temperature
• Apnea (pauses in breathing)
• Slowed heart rate
• Low blood pressure

When Should You Suspect Necrotizing Enterocolitis?

If you notice symptoms in your baby similar to those listed above, talk to your doctor. They may indicate the presence of necrotizing enterocolitis.

Is Pneumatosis Intestinalis an Infection?

Pneumatosis intestinalis (PI) refers to the presence of gas inside the wall of the small or large intestine. While gas inside the intestines is normal, gas in the wall of the intestine is not and can create a “bubbly” appearance.

PI in infants is usually associated with NEC and is a sign that shows up on X-rays. It indicates that the bowel wall has been damaged, which is a hallmark sign of NEC.

What Are the Stages of NEC?

How doctors treat NEC varies depending on the severity of the disease. Three identified stages of NEC indicate severity:

1. Stage 1: This is where doctors suspect that the baby may have NEC. The baby is likely demonstrating symptoms such as bloody stools, sluggishness, a slow heart rate, abdominal bloating, vomiting, and/or unstable body temperature.
2. Stage 2: This is where doctors have tested and diagnosed the baby with NEC. It includes all the symptoms of stage 1, as well as other symptoms like elevated blood platelet levels, pain in the abdomen, reduced or no intestinal movement, gas-filled spaces in the intestinal walls (pneumatosis intestinalis or PI), elevated lactic acid levels, and no bowel sounds.
3. Stage 3: This is considered an advanced form of NEC, and is the most serious. It includes symptoms from stages 1 and 2, as well as additional symptoms including low blood pressure, lowered number of certain white blood cells, inflammation in the abdominal tissues, apnea (periods of not breathing), blood clot formation, increased abdominal pain and redness, excess acid, increased build-up of gas in the abdominal cavity, and a stop in urination.

What is NEC Stage 3?

As noted above, stage 3 NEC is the most severe form of the disease. It indicates that the infant is severely ill, and is suffering not only from inflammation and infection in the intestines, but other systemic conditions like high blood pressure, apnea, and pain. There is also a risk of respiratory or circulatory arrest at this stage.

What Anatomical Problem Would Most Likely Lead to the Symptoms Associated with NEC?

NEC causes the tissues in the large intestine to become inflamed. This injures the intestines and can cause the death of intestinal tissues. In more severe cases, it can create actual holes (perforations) in the intestinal wall, which can then allow bacteria to escape into the rest of the body. If this happens, it can cause a life-threatening infection called sepsis.

Is It Normal for a Baby to Have a Big Tummy?

A baby’s abdomen (belly) normally appears somewhat full and rounded, particularly after a large feeding. It’s also normal for babies to have gas and to appear bloated. Between feedings, though, the tummy should feel soft and pliable. 

It can be difficult to determine, then, whether your baby’s full tummy is normal or if it may be a symptom of NEC. In most cases, it will be normal. If you notice other symptoms listed above, though, or if the baby’s tummy seems sensitive to the touch or discolored, check with your doctor right away.

How Is NEC Diagnosed?

When doctors observe symptoms like those listed above, they may test for NEC. Usually, an abdominal X-ray is all that’s needed to diagnose the condition. If the X-ray reveals a “bubbly” appearance in the wall of the intestine or air outside of the infant’s intestine, that confirms the diagnosis.

Other signs of NEC that can be seen in an X-ray include air in a vein of the liver called the portal vein, swollen intestines, and a lack of gas in the abdomen.

Doctors may also perform blood tests and stool tests to check for NEC.

What Is the Treatment for Necrotizing Enterocolitis?

Treatment for necrotizing enterocolitis typically involves a series of steps, including the following:

• Stopping all regular feedings, to give the intestines a break.
• Then feeding the baby through an intravenous catheter to help avoid the digestive process.
• Placement of a tube from the nose into the stomach. This tube removes air and fluids from the baby’s stomach and intestine, relieving swelling and discomfort.
• Frequent blood tests to detect early signs of an infection, or other problems in the body.
• Antibiotic therapy to kill any damaging bacterial infection.
• Assisted breathing if needed.
• Blood transfusions if needed.
• Surgery is a last resort, if the baby doesn’t respond to other medical treatment, or if the intestine is found to be perforated or significantly damaged.

What Antibiotics Are Used to Treat Necrotizing Enterocolitis?

Doctors may use a variety of different antibiotics to treat necrotizing enterocolitis (NEC). These may include the following:

• Ampicillin
• Gentamicin
• Cefotaxime
• Clindamycin
• Metronidazole
• Vancomycin

How Long Does Enterocolitis Last?

In most cases, with treatment, NEC will be gone within 10-14 days, after which the baby can start feeding again by mouth. If the baby doesn’t get better in that time, or if they show signs of more severe disease indicating bowel damage, they may require surgery.

How Does NEC Cause DIC?

Disseminated intravascular coagulation (DIC) is a rare and serious blood clotting disorder that can result in a few problems:

• Proteins in the blood that normally form blood clots may become abnormally active throughout the body, creating small blood clots in the blood vessels.
• As a result of these blood clots, the blood may not be able to deliver oxygen and nutrients to crucial organs like the lungs, heart, and brain.
• In some cases, the clotting proteins in the blood may be consumed and run out. This can create a risk of uncontrollable bleeding.

DIC is always caused by some other condition, such as an infection or injury. It is known that NEC can cause DIC in some cases, usually when the NEC is severe.

In one 2003 study, scientists noted that in severe NEC infections, the resulting inflammation in the intestines can lead to DIC. It is still unclear why DIC may occur in some infants with severe NEC, however.

In a later 2012 review, scientists found that DIC, along with other blood-flow abnormalities, were “frequent events” in NEC, and could play a role in intestinal damage.

What Are the Long-Term Effects of Necrotizing Enterocolitis?

Some premature infants recover from NEC and go on to enjoy normal lives. Those with more severe cases, however, may have lasting complications. These may include:

• Delays in neurodevelopment
• Failure to thrive
• Gastrointestinal problems (like strictures and adhesions)
• Cholestasis (liver disease)
• Short bowel syndrome
• Intestinal blockage
• Intestinal failure

Is Infant Formula Toxic?

Though infant formula is generally considered safe, there have been concerning reports lately about contamination.

In 2017, Clean Label Project revealed that it had found arsenic in 80 percent of baby products tested, including infant formula. In total, they tested 530 products and found that 65 percent of them tested positive for arsenic, 36 percent for lead, 58 percent for cadmium, and 10 percent for acrylamide. All of these chemicals pose potential dangers for developing infants. 

On August 16, 2018, consumer advocate publication Consumer Reports revealed that it had analyzed 50 nationally distributed packaged foods made for babies and toddlers, and found that every product had measurable levels of at least one of these heavy metals: lead, cadmium, mercury, and inorganic arsenic.

Congress tasked a subcommittee to investigate, and in February 2021, the committee confirmed the prior reports. The Food and Drug Administration (FDA) is now working to put into place new requirements that will do more to ensure baby formula and other baby food products are free or nearly free of these types of contaminants.

Baby formula may also be dangerous to premature and low birth weight infants. These babies have not yet fully developed their defense systems and may suffer from toxic effects in their intestines if fed infant formula.

What Are the Side Effects of Soy Formula?

Soy formula is considered an alternative to cow’s-milk formula, but research has shown some concern with high consumption of soy products.

In a 2018 study, for instance, researchers investigated soy formula compared to cow’s-milk formula and breast milk. They found that infants who consumed soy-based formula as newborns had some reproductive-system cells and tissues, compared to the other two groups. The differences, measured months after birth, were subtle but suggested a need for additional studies.

The concern is that soy-based formulas contain estrogen-like compounds that may affect the body’s endocrine system and potentially interfere with normal hormonal development. Scientists don’t yet know the long-term effects but believe it should be investigated.

The National Institute of Environmental Health Sciences (NIEHS) also suggests caution. The organization states on its website that soy contains naturally occurring compounds that can act like the hormone estrogen in the body:

“Although there have been no specific health problems documented in human infants receiving soy formula, it is recognized that infants go through developmental stages that are sensitive to estrogens…In some cases, the health effects resulting from a soy-based diet may not be apparent until years later.”

What Baby Formula is Safest?

Breast milk is considered the best option when it comes to feeding a baby. The Centers for Disease Control and Prevention (CDC) states that it provides “unmatched health benefits for babies and mothers,” and is the “gold standard for infant feeding and nutrition.”

For mothers who are unable to breastfeed, infant formula can provide an alternative. It is best to avoid it in premature infants, however, and to choose human-doner milk instead. Once the baby is well again, he or she should be able to tolerate infant formula.  

We don’t have any studies comparing infant formulas to see which may be closest to breast milk. Manufacturers are adding ingredients like lactoferrin and DHA to try to supplement the nutrients a baby needs. It’s always best to ask your doctor what he or she recommends.

What Formula Do Pediatricians Recommend?

There is no one best formula. Instead, different babies require different formulas to meet their health needs.

It’s always best to talk to your pediatrician about infant formula. Your baby may have unique requirements that demand a different type of formula than another baby. Your pediatrician can guide you based on your baby’s unique condition.

Which Formula is Closest to Breast Milk?

No commercial baby formula is close to breast milk. Manufacturers may advertise their products as being similar to breast milk, but to date, they have no evidence to back up these claims.

Some manufacturers have added various supplements to their formulas in an attempt to make them more similar to breast milk, but studies differ on whether these supplements are helpful or not when it comes to promoting infant health.

Does Similac Contain Cow’s Milk?

Most types of Similac infant formula contain nonfat milk and whey protein concentrate from cow’s milk. Similac also produces, however, a soy-based infant formula, as well as a hypoallergenic one that is free of lactose and milk proteins.