A new study aims to investigate whether antibiotic use during pregnancy affects the composition of breast milk, potentially altering a newborn's gut microbiome and immune system. Researchers in Milan, Italy, propose a comprehensive case-control study to evaluate how maternal antibiotic treatment impacts breast milk immunoglobulin A (IgA) levels and neonatal gut microbial health. The findings could provide critical insights for mothers and healthcare providers regarding the effects of antibiotics on neonatal well-being.

Potential Effects on Breast Milk Composition and Immune Function

The research team hypothesizes that prolonged antibiotic consumption during pregnancy may reduce breast milk IgA levels and disrupt the entero-mammary pathway, which is crucial for transferring protective antibodies from the mother to the infant. This disruption could impair the neonate's gut immune defense, making them more susceptible to infections. Additionally, changes in breast milk composition might influence the developing microbiome of the newborn, impacting their long-term health outcomes.

To explore these potential effects, the study will recruit two groups of 41 mother-infant pairs each. One group will include women who received at least seven consecutive days of antibiotic treatment during the final stages of pregnancy, while the other will consist of women with no antibiotic exposure. Investigators will analyze breast milk samples for IgA levels using ELISAs and assess gut microbiota through magnetic cell sorting and shotgun genomic techniques. These methods will provide detailed insights into microbial changes and immune responses, helping to determine if prenatal antibiotics alter the protective qualities of breast milk.

Implications for Neonatal Gut Microbiome and Long-Term Health

The study also seeks to understand how alterations in breast milk composition affect the neonatal gut microbiome and immune system. Research suggests that newborns rely heavily on breast milk IgA for early gut protection, and any reduction in this vital component could leave infants vulnerable to infections. Furthermore, disruptions in the symbiotic relationship between gut microbes and the immune system can have far-reaching consequences, including increased risks of conditions like atopy, obesity, and necrotizing enterocolitis.

By examining the interplay between breast milk components and neonatal gut health, researchers hope to shed light on the complex bidirectional relationship between the microbiome and immune function. The study will follow participants for one year, collecting data at multiple time points to monitor changes in gut bacteria and immune markers. At the 8-12 month follow-up, investigators will also assess neurodevelopmental outcomes using the Ages and Stages Questionnaire (ASQ-3). These assessments will provide valuable information about the long-term implications of prenatal antibiotic exposure, guiding future clinical guidelines and informing decisions about antibiotic use during pregnancy.