What is already known
Antibiotic use in childhood is linked to higher risks of conditions such as diabetes and asthma. While current guidelines recommend giving antibiotics to mothers before C-sections to prevent infections — a procedure that exposes newborns to the drugs, the effects of this exposure on the infant’s gut microbiota are not well understood.
What this research adds
Researchers analyzed the microbiota from 79 infants born to mothers that received antibiotics during C-sections. How the babies were fed affected gut microbial diversity, species composition, and the levels of specific metabolites more than antibiotic use did. Infants fed with formula, for example, showed differences in their microbiota compared to breastfed infants. Feeding mode explained 12% of the variation in gut microbiota composition during the first six weeks of life.
Conclusions
The findings suggest that while antibiotics can cause changes to the infant microbiota, they are much less significant than the impact of feeding mode.
Antibiotic use in childhood is linked to higher risks of conditions such as diabetes and asthma, leading to efforts to reduce unnecessary antibiotic use in infants. New research now suggests that antibiotic use during C-section has limited impact on the infant gut microbiota.
The findings, published in Cell Host & Microbe, reveal that while antibiotics can cause changes to the infant microbiota, they are much less significant than the impact of feeding mode.
“We decided to conduct this study because it addresses a significant clinical question with possibly profound implications for infant health,” says study lead investigator Trishla Sinha at the University of Groningen in the Netherlands. “It is crucial to balance high-quality evidence of immediate benefits to the mother against equally robust evidence of any potential short- and long-term risks to the infant. Mothers often ask whether the antibiotics they take influence their child, and this study can provide assurance that they have only small effects on infant gut microbiome.”
Current guidelines recommend giving antibiotics to mothers before C-sections to prevent infections — a procedure that exposes newborns to the drugs. However, the effects of this exposure on the infant’s gut microbiota are not well understood.
So, Sinha and her colleagues set out to analyze the microbiota from 79 infants born to mothers that received antibiotics during C-sections.
Feeding vs. antibiotics
The study included 28 mother-infant pairs: 12 mothers received antibiotics before the C-section and 16 after the umbilical cord was clamped. The researchers collected 172 stool samples from babies at eight different time-points during their first year of life. The analysis also included data from two other similar trials, bringing the total number of infants to 79.
The team analyzed the samples for gut microbiota composition, strain variability, and the presence of antibiotic-resistance genes. They also examined bile and short-chain fatty acids — two types of metabolites that play crucial roles in the gut microbiota and overall health. Along with data on antibiotic use, the researchers also collected information on whether the infants were formula-fed or breastfed.
Feeding mode affected gut microbial diversity, species composition, and the levels of specific metabolites more than antibiotic use did. Infants fed with formula, for example, showed differences in their microbiota compared to breastfed infants. Feeding mode explained 12% of the variation in gut microbiota composition during the first six weeks of life.
Subtle impacts
Although more studies are needed to confirm these findings, they suggest that how babies are fed in early life could have important long-term consequences. Antibiotics, in contrast, may only have subtle impacts on the gut microbiota.
“We were surprised that the antibiotics did not drastically alter the microbiome, because other research has reported a large impact of antibiotics on infant gut microbiome composition,” Sinha says. “This is probably due to the fact that it is a one-time exposure to intravenous antibiotics during birth in contrast to prolonged exposure to antibiotics throughout infancy.”
The team now plans to study 1,500 mother-infant pairs from the Dutch Lifelines NEXT cohort — a large study in the Netherlands designed to explore the relationship between genetic, environmental and lifestyle factors. Sinha and her colleagues aim to understand how various factors during pregnancy, birth and the postnatal period could affect the infant gut microbiota.
