A nationwide Swedish study suggests that daily probiotic supplementation containing Bifidobacterium infantis, lactis and Streptococcus thermophilus significantly reduces the risk of necrotising enterocolitis and death among very preterm infants, supporting targeted probiotic use in neonatal care.
A nationwide Swedish study has found that daily probiotic supplementation in very preterm babies was linked with lower rates of necrotising enterocolitis and death, while offering no clear reduction in sepsis. The findings, published in JAMA Network Open, add to a growing body of evidence suggesting that carefully selected probiotic mixtures may help protect some of the most vulnerable newborns. According to the study, the benefit was seen in infants born before 32 weeks of gestation who received a multistrain product containing Bifidobacterium infantis, Bifidobacterium lactis and Streptococcus thermophilus.
Necrotising enterocolitis, often shortened to NEC, is a serious intestinal disease that mainly affects premature babies whose digestive systems are still developing. It can cause inflammation and damage to the bowel, and in severe cases may require surgery. Researchers have long suspected that probiotics, which are live microorganisms intended to support health when given in sufficient amounts, might help by influencing the gut microbiome and reducing harmful bacterial growth. Earlier studies, including meta-analyses and randomised trials, have reported lower NEC rates and reduced mortality among preterm infants given probiotics, although the strength of evidence has varied by strain, setting and study design.
The Swedish data offer one of the clearest real-world tests of a national probiotic policy. After the Swedish Neonatal Society recommended probiotic use in very preterm infants in 2020, uptake rose sharply, from 16.9% that year to an average of 64.8% between 2021 and 2024. In the full cohort of 4,695 infants, the combined rate of death or NEC was lower among those given probiotics than among those who received none. The researchers also reported that part of the mortality benefit appeared to be explained by the reduction in NEC, suggesting that prevention of bowel disease may be one pathway through which probiotics improve outcomes.
Still, the study did not show a meaningful drop in sepsis, a bloodstream infection that remains a major concern in neonatal intensive care. That result is consistent with some earlier research, including an Australian and New Zealand trial using the same bacterial strains, although other studies in England and Wales have suggested a modest sepsis benefit. The Swedish authors also noted that no cases of probiotic-related sepsis were reported in a survey of neonatal intensive care units during the supplementation period, but they warned that safety monitoring remains important because risks such as contamination or bacterial translocation cannot be ruled out entirely.
The findings should also be interpreted with caution. The Swedish recommendation did not initially cover extremely preterm babies born before 28 weeks because evidence was considered insufficient at the time, and the new analysis should not be extended to that group without further study. The authors also acknowledged the limitations of register-based research, including possible misclassification of NEC cases. Even so, the results strengthen the case for probiotic use in selected very preterm infants and may help clinicians and families weigh the potential benefits alongside the remaining uncertainties.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
