Antenatal Prebiotic Supplementation Fails to Prevent Atopic Dermatitis in High-Risk Infants: Insights from the PREGRALL Trial

Introduction: The Quest for Primary Prevention in Atopy

Atopic dermatitis (AD) represents one of the most prevalent chronic inflammatory skin diseases in childhood, often serving as the initial step in the so-called atopic march toward asthma and allergic rhinitis. Despite advancements in topical and systemic therapies, the medical community remains focused on a primary goal: prevention. Emerging evidence has long suggested that the early-life gut microbiome plays a pivotal role in immune system maturation. This has led to the hypothesis that modulating the maternal or infant microbiota through prebiotics—non-digestible carbohydrates that stimulate the growth of beneficial bacteria—could induce immune tolerance and prevent allergic diseases.

While postnatal prebiotic supplementation has been studied extensively, the prenatal period is increasingly recognized as a critical window for immune priming. Preclinical models had previously indicated that maternal intake of galacto-oligosaccharide (GOS) and inulin could reduce the risk of food allergies in offspring. However, translating these findings into clinical practice requires rigorous human trials. The PREGRALL trial was designed to address this specific gap: can antenatal prebiotic intervention protect high-risk infants from developing atopic dermatitis?