Daily supplementation with a multistrain probiotic formula significantly lowers the risk of death and necrotizing enterocolitis in very preterm infants, according to a study published yesterday in JAMA Network Open. Researchers from Sweden’s Karolinska Institutet found that implementing a national recommendation for probiotics dropped the rate of death and the severe gastrointestinal disease among very premature infants from 3.4% to 1.5%.
Swedish Registry Data Shows 72% Lower Risk
The research team examined data from the Swedish National Quality Registry covering premature infants admitted to 38 neonatal intensive care units from 2017 through 2024. Investigators focused specifically on infants born between 28 weeks and 31 weeks gestation. Following a 2020 national recommendation by the Swedish Neonatal Society, probiotic use across these units climbed from 0% to 65% by 2024.
Out of 4,695 infants included in the analysis, 1,571 received the probiotic formula while 3,124 did not. The formula combined Bifidobacterium infantis Bb-02, Bifidobacterium lactis BB-12, and Streptococcus thermophilus TH-4. Results showed that probiotic supplementation was associated with a 72% lower risk of the combined outcome of death and necrotizing enterocolitis, a severe condition driven by microbial imbalance and the overgrowth of pathogenic gut bacteria.
Evaluating Safety and Probiotic-Associated Sepsis
Safety remains a primary consideration for clinicians evaluating microbial supplementation in vulnerable preterm populations. Investigators specifically tracked rates of sepsis alongside mortality and gastrointestinal outcomes. The study revealed no significant increase in the risk of death or sepsis among infants who received the daily formula.
“Regarding probiotic-associated sepsis, no cases during the implementation period were reported when we surveyed Swedish NICUs, which is reassuring and supports the safety of this strategy,” the study authors wrote. They added that families should be informed about this positive benefit-risk profile.
Did you know? Necrotizing enterocolitis occurs when a microbial imbalance triggers a loss of beneficial bacteria in the gut, making it a leading cause of illness and death in preterm infants.
International Uptake Contrasts With US Cautions
Adoption rates in Swedish neonatal units mirror trends seen in other nations. Registry data shows probiotic uptake reached 67% in Canada for infants born before 34 weeks in 2022, and 54% in England and Wales during the same year. By contrast, adoption in the United States remains low due to regulatory classifications and safety warnings.
A previous evaluation of 807 US neonatal units showed only 17% had adopted routine probiotic use by 2019. In 2021, the American Academy of Pediatrics cautioned against routine use in infants weighing less than 2.2 pounds, citing mixed efficacy data. The Food and Drug Administration subsequently issued a safety warning in September 2023 after a preterm infant died of sepsis following administration of a single-strain probiotic.
Writing in an accompanying commentary, Ravi Patel of the Emory University School of Medicine and Children’s Healthcare of Atlanta noted that Sweden’s rapid implementation “stands in stark contrast to the concerning situation in the US.” He pointed out that the findings highlight how national guidelines can reduce the disease burden and improve survival.
Frequently Asked Questions
What causes necrotizing enterocolitis in preterm infants?
Necrotizing enterocolitis develops from a microbial imbalance in the gut, featuring a loss of beneficial bacteria that allows pathogenic bacteria to overgrow and damage gastrointestinal tissue.
Which probiotic strains were tested in the Swedish study?
The formula evaluated in the research contained Bifidobacterium infantis Bb-02, Bifidobacterium lactis BB-12, and Streptococcus thermophilus TH-4.
Why is probiotic use less common in United States neonatal units?
US adoption remains low following American Academy of Pediatrics cautions and an FDA safety warning issued to healthcare providers regarding sepsis risks tied to dietary supplement products.
What are your thoughts on implementing national probiotic guidelines in neonatal units? Share your perspective in the comments below, and subscribe to our newsletter for the latest clinical research updates.
Related reading