New research from The Kids Research Institute Australia suggests a simple dietary intervention during pregnancy could help protect against the increased risk of food allergies associated with antibiotics taken before birth.
The findings, published in the international journal Allergy, show that among mothers who received antibiotics during labour, those who supplemented with a prebiotic during pregnancy did not have an increased risk of their baby developing food allergy.
In contrast, children born to mothers who received antibiotics but did not take prebiotics were more than five times more likely to develop a food allergy.
Lead author and Research Assistant at The Kids Research Institute Australia, Summer Walker, said around one in every four Australian mothers received antibiotic treatment during pregnancy, and up to half of infants were administered antibiotics in their first year of life.
“There has been increasing concern regarding the potential link between antibiotics and food allergies, with maternal antibiotic use during pregnancy shown to be associated with a higher risk of child eczema and food allergies,” Ms Walker said.
“We know that prebiotics promote the growth of healthy gut bacteria, while antibiotics disrupt the gut microbiome, by reducing diversity and potentially lead to a gut microbiome imbalance. During pregnancy this can potentially result in long-term child health effects.”
Lead author and Research Assistant, Summer Walker
Antibiotics are often essential during labour and save lives, so they should always be used when needed. This research suggests there may be a simple way to reduce some of the potential long-term health effects for children, such as food allergies, by mothers consuming prebiotics during pregnancy.
As part of the SYMBA trial in Western Australia, researchers followed 652 pregnant women and their babies – the majority from ORIGINS, Australia’s largest longitudinal birth cohort of its kind - from mid-pregnancy until one year of age. Women consumed either a prebiotic or a placebo supplement from mid-pregnancy until their baby was six months old.
All babies had a family history of allergic disease, and more than 80 per cent of mothers and 20 per cent of babies received antibiotics during the study intervention period.
“Among mothers who did not take prebiotics, antibiotic exposure during labour was associated with a more than five‑fold increase in food allergy risk in babies,” Ms Walker said.
“Our findings suggest a particularly vulnerable period around birth where antibiotic use may negatively influence a baby’s developing immune system.”
Previous research has often grouped together antibiotics given during labour and those given for caesarean births. In this study, researchers looked at these separately.
“Antibiotic levels peak in the umbilical cord within 30 minutes and remain bactericidal for several hours, regardless of labour duration. Consequently, labour antibiotics may have a greater impact on the infant microbiome due to longer fetal exposure,” Ms Walker said.
“This research is an important first step and opens the door to exploring whether prebiotics could also help protect against other child health conditions linked to antibiotics.
“For now, it’s best for women to follow existing dietary advice and speak with their healthcare provider before starting supplements.
“The good news is that many healthy diets, such as the Mediterranean diet, are rich in prebiotic containing foods such as garlic, leeks, onions, asparagus and legumes.”
First published Thursday 16 July 2026.
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