Probiotics in Pregnant Women to Prevent Allergic Disease: a Randomized, Double-blind Trial

Background: Previous reports have suggested that certain probiotics given to mothers and children at risk of atopy halves the incidence of atopic dermatitis (AD) at 2 years of age.

Objectives: To examine if probiotics given to pregnant women in a nonselected population could prevent atopic sensitization or allergic diseases during the child's first 2 years.

Methods: In a randomized, double-blind trial of children from a nonselected maternal population (ClinicalTrials.gov identifier: NCT00159523), women received probiotic milk or placebo from 36 weeks of gestation to 3 months postnatally during breastfeeding. The probiotic milk contained Lactobacillus rhamnosus GG, L. acidophilus La-5 and Bifidobacterium animalis subsp. lactis Bb-12. Children with an itchy rash for more than 4 weeks were assessed for AD. At 2 years of age, all children were assessed for atopic sensitization, AD, asthma and allergic rhinoconjunctivitis. The intention-to-treat (ITT) analysis was enabled by multiple imputations.

Results: Four hundred and fifteen pregnant women were computer randomized. At 2 years, 138 and 140 children in the probiotic and the placebo groups, respectively, were assessed. In the ITT analysis, the odds ratio (OR) for the cumulative incidence of AD was 0·51 in the probiotic group compared with the placebo [95% confidence interval (CI) 0·30-0·87; P=0·013]. There were no significant effects on asthma (OR 0·68, 95% CI 0·26-1·80; P=0·437) or atopic sensitization (OR 1·52, 95% CI 0·74-3·14; P=0·254).

Conclusions:   Probiotics given to nonselected mothers reduced the cumulative incidence of AD, but had no effect on atopic sensitization.