Research shows that giving very premature infants a specific probiotic supplement significantly reduces their risk of death and serious gut disease. According to Gram Research analysis of a 2026 Swedish cohort study of 4,695 infants, babies receiving probiotics had a death rate of 0.3% compared to 1.4% in babies without probiotics, and serious gut disease rates dropped from 2.5% to 0.6%. The probiotic did not prevent blood infections, suggesting its benefits are specific to intestinal protection.
A major Swedish study of nearly 5,000 very premature infants found that giving babies a specific probiotic supplement significantly reduced their risk of death and a serious gut disease called necrotizing enterocolitis (NEC). According to Gram Research analysis, babies who received the probiotic had death rates of 0.3% compared to 1.4% in babies who didn’t receive it. The study, published in 2026, tracked infants born between 28 and 31 weeks of pregnancy and found the probiotic was safe and effective, though it didn’t prevent blood infections. These findings could help doctors and parents make better decisions about probiotic use in premature infant care.
Key Statistics
A 2026 Swedish cohort study of 4,695 very premature infants found that probiotic supplementation reduced death rates from 1.4% to 0.3%, representing an 79% relative risk reduction.
Among 4,695 very premature infants in a 2026 Swedish study, serious gut disease (necrotizing enterocolitis) occurred in 0.6% of babies receiving probiotics compared to 2.5% of babies without probiotics.
A 2026 population-based cohort study of 4,695 very premature infants found that probiotics reduced the combined risk of death and serious gut disease from 3.4% to 0.8%, with about 42% of the mortality benefit mediated through reduced gut disease.
In a 2026 Swedish study of 4,695 very premature infants, probiotic supplementation did not reduce blood infection rates, which remained at 3.4% in the probiotic group versus 4.4% in the control group.
The Quick Take
- What they studied: Whether giving premature babies a probiotic supplement (beneficial bacteria) could reduce their risk of death, a serious gut disease, or blood infections.
- Who participated: 4,695 very premature infants born between 28 and 31 weeks of pregnancy in Sweden between 2017 and 2024. About 54% were boys, and the average gestational age was 30.2 weeks.
- Key finding: Babies receiving probiotics had a 0.3% death rate compared to 1.4% in babies without probiotics. The probiotic also cut the risk of serious gut disease from 2.5% to 0.6%.
- What it means for you: For parents of very premature babies, this research suggests probiotics may be a safe option worth discussing with doctors. However, these results apply only to babies born between 28 and 31 weeks, not extremely premature infants born before 28 weeks.
The Research Details
Researchers looked at medical records from Swedish hospitals for premature babies born over 8 years (2017 to 2024). In 2020, Sweden recommended giving very premature babies a specific probiotic mixture containing three types of beneficial bacteria. This natural change in practice allowed researchers to compare babies who received probiotics with those born before the recommendation when probiotics weren’t routinely given. The probiotic contained 1 billion units of freeze-dried bacteria and was given daily starting at birth until the baby reached 34 weeks of development. Researchers used several statistical methods to account for differences between babies who did and didn’t receive probiotics, ensuring fair comparisons.
This study design is powerful because it looks at real-world medical practice rather than a controlled experiment. When a whole country changes its medical recommendations, researchers can compare outcomes before and after the change. This approach captures how probiotics work in actual hospital settings with diverse patients, making the results more relevant to real clinical practice than laboratory studies.
This is a large, population-based study using official medical records from all Swedish hospitals, which reduces bias and captures nearly all very premature infants born during the study period. The researchers used multiple statistical methods to verify their findings, which strengthens confidence in the results. However, the study cannot prove that probiotics directly caused the improvements because it observes what happened rather than randomly assigning babies to receive probiotics or not.
What the Results Show
Babies who received the probiotic supplement had significantly lower rates of death and serious gut disease compared to babies born before probiotics were recommended. The death rate dropped from 1.4% to 0.3%, and the rate of serious gut disease fell from 2.5% to 0.6%. When researchers looked at these conditions together, the probiotic group had a 0.8% rate compared to 3.4% in the non-probiotic group. The researchers estimated that about 42% of the mortality benefit came from preventing gut disease, suggesting the probiotic works partly by protecting the baby’s intestines. The probiotic was well-tolerated with no safety concerns reported.
Interestingly, the probiotic did not reduce the risk of blood infections (sepsis), which occurred in 3.4% of the probiotic group and 4.4% of the non-probiotic group. This suggests the probiotic’s benefits are specific to preventing death and gut disease rather than being a general infection fighter. The researchers also confirmed their findings using multiple statistical approaches, all showing similar protective effects.
Earlier smaller studies suggested probiotics might help premature infants, but this is one of the largest real-world studies confirming those benefits in a specific population. The findings align with some previous research showing probiotics can protect the developing gut in premature babies. However, this study is more definitive because it includes thousands of infants and uses national medical records rather than data from single hospitals.
The study only applies to babies born between 28 and 31 weeks of pregnancy, so results cannot be assumed for extremely premature infants born before 28 weeks. Because the study observes what happened rather than randomly assigning babies to receive probiotics, other factors could have contributed to the improvements. The specific probiotic mixture used in this study may not be the same as other probiotic products available elsewhere, so results may not apply to different formulations.
The Bottom Line
For very premature infants born between 28 and 31 weeks, probiotic supplementation appears beneficial and worth discussing with neonatal doctors. The evidence is strong that probiotics reduce death and serious gut disease risk. Parents should not assume these benefits apply to extremely premature infants or use different probiotic products without medical guidance. Confidence level: Moderate to High for the studied population.
Parents expecting very premature babies (28 to 31 weeks gestation) should discuss probiotics with their neonatal team. Neonatal doctors and hospital administrators can use this evidence to inform probiotic policies. These findings do not apply to babies born at term (full pregnancy) or extremely premature infants born before 28 weeks.
The probiotic was given from birth through 34 weeks of development. The protective effects on death and gut disease were measured throughout the hospital stay, typically several weeks to months depending on the baby’s health.
Frequently Asked Questions
Do probiotics help prevent death in premature babies?
Research shows probiotics significantly reduce death risk in very premature infants born between 28 and 31 weeks. A 2026 Swedish study of 4,695 infants found death rates dropped from 1.4% to 0.3% with probiotic supplementation, though these results don’t apply to extremely premature infants born before 28 weeks.
What is necrotizing enterocolitis and how do probiotics help?
Necrotizing enterocolitis (NEC) is a serious gut disease that damages premature infants’ intestines. Probiotics appear to protect the developing gut by promoting beneficial bacteria. A 2026 study found NEC rates dropped from 2.5% to 0.6% with probiotic use in very premature infants.
Are probiotics safe for premature babies?
The 2026 Swedish study of 4,695 very premature infants found no safety concerns with the specific probiotic mixture tested. However, safety may vary with different probiotic products, so parents should only use probiotics recommended by their neonatal medical team.
Can probiotics prevent infections in premature infants?
Probiotics did not reduce blood infection rates in the 2026 study, which remained around 3.4% to 4.4% regardless of probiotic use. This suggests probiotics protect the gut specifically rather than preventing all types of infections in premature babies.
Which premature babies should receive probiotics?
This research applies specifically to very premature infants born between 28 and 31 weeks of pregnancy. Results should not be assumed for extremely premature infants born before 28 weeks or babies born at term. Parents should discuss probiotic use with their neonatal care team.
Want to Apply This Research?
- Parents of very premature infants can track probiotic administration dates and times in a health app, noting any changes in feeding tolerance, stool patterns, or clinical status to share with the neonatal care team.
- If a doctor recommends probiotics, set daily reminders to ensure consistent administration at the same time each day, and maintain a simple log of doses given to confirm adherence and discuss with the medical team.
- Track feeding progress, bowel movements, and any signs of feeding intolerance (vomiting, abdominal distension) weekly. Share this information with the neonatal team to monitor for any changes in gut health or complications.
This research applies specifically to very premature infants born between 28 and 31 weeks of pregnancy and should not be generalized to extremely premature infants (born before 28 weeks) or full-term babies. Probiotic products vary significantly in composition and quality. Parents of premature infants should discuss any probiotic supplementation with their neonatal care team before starting treatment. This article summarizes research findings and does not constitute medical advice. Always consult with qualified healthcare providers regarding your infant’s specific medical needs and treatment options.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.