Early Life Antibiotic Exposure & Autism

Early life antibiotic exposure shows no association with autism spectrum disorder (ASD). A recent study including all live births in Manitoba, Canada between 1998 and 2016 looked at antibiotic exposure (defined as having filled one or more antibiotic prescriptions in the first year of life) and ASD diagnosis. The study found that antibiotic exposure (both number of treatment courses and cumulative duration of antibiotic exposure) was not associated with ASD, and researchers concluded that the lack of a significant association between antibiotics and ASD “should provide reassurance to concerned prescribers and parents”. International Journal of Epidemiology

→Takeaway: While this study aims to answer the question, is exposure to antibiotics in the first year of life a risk factor for developing ASD, it fails to take into account some important factors. First, while the researchers looked at the number of antibiotic prescriptions filled in the first year of life, we all know that a filled prescription does not mean the patient actually took the medication. Second, antibiotic exposure often begins well before birth – in the womb and during the birthing process. Past studies have found a strong association between ASD and antibiotic exposure in early life as well as exposure in the womb. Lastly, ASD is associated with increased GI symptoms and imbalanced gut bacteria (which are worsened by antibiotics). While we don’t know whether an altered microbiome is a result of ASD, or its cause, it’s best to avoid antibiotic exposure before, during, and after birth.