Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant.

Randomized, placebo-controlled study in pregnant women with atopic sensitization and either a history of or active allergic disease who intended to breastfeed for at least 2 months. The trial was conducted at a single tertiary center in Turku, Finland, and followed high-risk infants after maternal probiotic supplementation during late pregnancy and early breastfeeding.

Two maternal probiotic regimens were tested: LPR1BL999, containing Lactobacillus rhamnosus LPR (CGMCC 1.3724) plus Bifidobacterium longum BL999 (ATCC: BAA-999), and ST111BL999, containing Lactobacillus paracasei ST11 (CNCM 1-2116) plus Bifidobacterium longum BL999. Each was given as 1 sachet daily, 7 g powder diluted in water, starting 2 months before the expected delivery date and continued during breastfeeding until the infant was 2 months old; the comparator was an identical supplement without probiotics.

Maternal probiotic supplementation reduced infant eczema risk through 24 months and lowered chronically persistent eczema, with no increase in adverse effects. Eczema up to age 24 months occurred in 21/73 (29%) in the LPR1BL999 group and 20/70 (29%) in the ST111BL999 group, versus placebo odds ratios of 0.17 (95% CI 0.08-0.35; P < .001) and 0.16 (95% CI 0.08-0.35; P < .001), respectively. Chronically persistent eczema was also reduced, with odds ratios of 0.30 (95% CI 0.12-0.80; P = .016) and 0.17 (95% CI 0.12-0.80; P = .003). Skin prick test positivity was not significantly changed, and no adverse effects related to probiotic supplementation were detected.

The study was relatively small and conducted at a single center in a Finnish high-risk population, which limits generalizability. Outcomes were driven by specific probiotic strain combinations, so effects may not apply to other probiotic products or dosing schedules. Some reported arm-level denominators differed across outcomes, indicating incomplete follow-up for certain endpoints.