Giving very premature babies a daily probiotic was linked to a lower risk of death and severe bowel disease, a large Swedish study has found.

The research from Karolinska Institutet, published in JAMA Network Open, analysed 4,695 babies born between 28 weeks and 31 weeks and six days from 2017 to 2024. Of these, 1,571 received a probiotic supplement and 3,124 did not.

Among babies given probiotics, 0.8 per cent died or developed necrotising enterocolitis, a serious intestinal disease, compared with 3.4 per cent of those who did not. The risk of death alone was 0.3 per cent against 1.4 per cent.

The daily supplement combined three bacterial strains delivering about one billion colony-forming units, started after birth and continued until postmenstrual week 34.

“Infants who received probiotics had a significantly lower risk of both NEC and death,” said Dr Ayoub Mitha, the study’s corresponding author.

The study is observational, and the authors said the findings should not be generalised to babies born before 28 weeks.