Maternal probiotic supplementation for prevention of morbidity and mortality in preterm infants.

Systematic review and meta-analysis of randomized trials in pregnant women at risk for preterm birth and mothers after delivery of preterm infants, including infants born preterm and very low birth weight infants. Active probiotic arms were compared mainly with placebo, no intervention, or, in the review question, neonatal probiotic administration.

Maternal probiotic supplementation was given either during pregnancy or after birth to mothers of preterm infants, compared with placebo or no intervention. Regimens varied across trials and included single-strain and multi-strain capsules such as Lactobacillus rhamnosus GG, Lactobacillus salivarius, Lactobacillus acidophilus, Bifidobacterium lactis, and related combinations, with doses ranging from about 10^8 CFU to 9 × 10^10 CFU and treatment durations that differed by study.

Overall, evidence was insufficient to show that maternal probiotics during pregnancy or after birth provide clear benefit or harm for preterm infants. When probiotics were given to mothers after birth for preterm infants, there was a potential reduction in time to reach 50% enteral feeds, but the estimate was extremely imprecise. The review did not establish meaningful effects on neonatal morbidity or mortality, and there were no direct data comparing maternal probiotic administration with neonatal probiotic administration. One trial reported reduced maternal mastitis, but the broader evidence base remained too limited and inconsistent for firm conclusions.

The evidence base was small and heterogeneous, with different probiotic strains, doses, and timing of administration across trials. Many outcomes were sparsely reported, estimates were often imprecise, and most data came from low-risk pregnancies rather than the high-risk populations of greatest interest. There were no direct trials comparing maternal with neonatal probiotic administration, and certainty was limited for postpartum use and key infant outcomes.