Probiotics in Pregnant Women to Prevent Allergic Disease: A Randomized, Double-Blind Trial

Abstract

To determine if probiotics given to pregnant and nursing women in a nonselected population could prevent allergic disease in the first 2 years of life.There were 278 children (138 on probiotics, 140 on placebo) from a population of 415 women in Trondheim, Norway.This was a randomized, double-blind, placebo-controlled study. Women were given 250 mL of probiotic milk or placebo milk per day from 36 weeks' gestation to 3 months after delivery while breastfeeding. The probiotic milk contained Lactobacillus rhamnosus, Lactobacillus acidophilus La-5, and Bifidobacterium animalis subsp lactis Bb-12. At 2 years, all children were assessed for atopic dermatitis (AD), asthma, allergic rhinoconjunctivitis, and atopic sensitization (positive skin-prick-test result or elevated specific immunoglobulin E [IgE] level). The intention-to-treat analysis was enabled by multiple imputations, and the complete-case analysis included all subjects who completed end-point exams.Using intention-to-treat analysis, the odds ratio (OR) for the cumulative incidence of AD was 0.51 for those in the probiotic group compared with those in the placebo group (95% confidence interval [CI]: 0.30–0.87]; P = .013). The effect was stronger for non–IgE-associated AD (OR: 0.43 [95% CI: 0.23–0.81]; P = .009). There was no effect on IgE-associated AD (OR: 0.90 [95% CI: 0.37–2.17]; P = .812). No significant effect was found for asthma, allergic rhinoconjunctivitis, or atopic sensitization. In complete-case analysis, there was a significant difference in the cumulative incidence of AD between the probiotic and placebo groups (log rank, P = .022), and the relative risk was 0.61 (95% CI: 0.41–0.91; P = .013; number needed to treat to benefit: 8). The hazard ratio was 0.58 (95% CI: 0.36–0.93) in the probiotic group compared with that in the placebo group (P = .024). There was a significantly (P = .044) reduced risk of having moderate AD compared with the placebo group.In a nonselected population of mothers, consumption of probiotics decreased the cumulative incidence of AD but had no effect on asthma, allergic rhinoconjunctivitis, or atopic sensitization.This study found that probiotic bacteria given to the mother during pregnancy and early lactation might prevent AD in the child. Previous randomized controlled trials that used various probiotics have involved administration directly to all or the majority of children. The results of this study are exciting in that treatment of the mother over a limited period of time seemed to make a difference in the cumulative incidence of AD and severity of atopic dermatitis in affected children.