Premature Infant Necrotizing Enterocolitis (NEC) Rates Decreased with Human Milk, Compared to Cow’s Milk Formula: Study

Researchers urge NICU units to adopt a default policy of feeding newborn preemies an exclusively human milk diet, to reduce NEC risks.

In what has become a virtually unanimous refrain from pediatricians over the last several years, a recent study finds that preterm infants given diets of exclusively human milk are less likely to develop a deadly condition known as necrotizing enterocolitis (NEC).

The findings were published in the medical journal Advances in Neonatal Care late last year, confirming that children born prematurely who are fed cow’s milk-based formula, like Similac or Enfamil, may be twice as likely to develop NEC, and were six times more likely to die in infancy.

NEC is a devastating gastrointestinal condition that occurs when harmful bacteria breaches the walls of the intestines, causing portions of the tissue to become inflamed or die. It primarily affects premature babies, and often results in the need for emergency surgery while the baby is still in the NICU. Many infants do not survive.

As a result of the failure of formula manufacturers to disclose the risk of NEC, hundreds of families are now pursuing Similac lawsuits and Enfamil lawsuits, claiming that their premature children could have avoided debilitating and often fatal injuries if earlier warnings had been provided for users and the medical community in recent years.

In this new study, researchers from Memorial Hospital in Savannah, Georgia, and from Troy University in Phenix City, Alabama, sought to directly compare the progress of extremely premature infants fed exclusive human milk diets (EHMDs), with those fed bovine-based formula.

The researchers, led by Dr. Lydia Harris, looked at data on 201 infants born before 32 weeks gestation, who weighed less than 1,250 grams and with low Apgar scores. They then looked at their rates of NEC, mortalities and other adverse health problems.

According to their findings, 10.5% of the infants fed products like Similac and Enfamil developed NEC, compared to only 4.8% of those who were breast fed, with or without human milk fortifier. In addition, the infants fed only human milk had a 1% mortality rate, while 6% of the infants fed cow’s milk-based formula died.

The researchers also noted that the infants fed human milk-exclusive diets showed a statistically significant greater amount of weight gain than their bovine formula-fed peers.

“Neonatal intensive care units should consider EHMDs for use in this infant population,” Harris’s team concluded. “Future research is needed to support dissemination of the use of EHMD as standard of practice.”

Research Links NEC Risk to Cow’s Milk Formula

Despite decades of claims by infant formula manufacturers that suggested their products were a safe alternative for premature infants, numerous studies published in recent years have highlighted the importance of breastfeeding or using human milk products for babies, which have been found to deliver the necessary nutrients a newborn needs to thrive, provide some key immunities already developed by the mother, and help the infant’s digestive tract develop.

Research has regularly shown cow’s milk-based baby formula products do not confer the same benefits as breastfeeding and may increase the risk that premature infants develop NEC, which frequently results in severe, life-long injuries or death.

A January 2022 study found that nutrients in breast milk play a critical role in helping the intestinal epithelial layer mature in preterm infants, strengthening their resistance to NEC. However, these nutrients are not present in cow’s milk-based infant formula marketed for premature babies, such as the popular Similac and Enfamil product lines.

In July 2022, the American Academy of Pediatrics (AAP) issued a policy statement calling for hospitals and the government to promote breastfeeding as the primary form of nutrition for newborns.

Another study, published last October, even found that preterm infants fed breast milk were less likely to develop asthma later in life.

2025 Premature Infant Formula NEC Lawsuit Update

Abbott Laboratories, the makers of Similac, and Mead Johnson, the manufacturer of Enfamil, both face hundreds of premature infant NEC lawsuits, which allege that false and misleading information has been provided for decades to families, hospitals and doctors, as part of a coordinated effort to increase sales of the formula products.

Since complaints filed throughout the federal court system each raise common questions of fact and law, an infant formula lawsuit MDL (multidistrict litigation) was established in 2022, centralizing the claims before U.S. District Judge Rebecca R. Pallmeyer in the Northern District of Illinois, for discovery and a series of early trial dates.

As part of the coordinated management of the federal litigation, Judge Pallmeyer previously established a “bellwether” program, where a small group of representative claims are being prepared for a series of early trial dates to help evaluate the strengths and weaknesses of the cases, and promote global NEC settlement negotiations.

In October 2024, Judge Pallmeyer announced that the first infant formula NEC bellwether trial would go before a jury on May 5, 2025, involving claims brought by plaintiff Ericka Mar over the death of her child RaiLee Mar. That will be followed by additional trials expected to begin on August 11, 2025, November 3, 2025, and February 2, 2026.

While the outcome of these early trials will not have any binding impact on NEC injury lawsuits being pursued by other families, the average payouts awarded by juries will likely have a substantial impact on the amount that Abbott and Mead Johnson may be required to pay in NEC injury settlements to avoid hundreds of additional claims going before juries.

If the parties fail to resolve the litigation following the federal bellwether trials, Judge Pallmeyer may start remanding dozens of individual claims back to U.S. District Courts nationwide for separate trial dates.