Higher Risk Observed in First and Second Trimester Exposures and Lasting Longer than 14 Days
Canadian researchers recently assessed whether prenatal exposure to antibiotics is associated with an increased risk of autism spectrum disorder (ASD) in offspring born at term. To investigate this hypothesis, the authors used a population-based retrospective cohort study that included mothers who delivered a live singleton-term infant in British Columbia between April 2000 and December 2014. Exposure was defined by the study as using antibiotic prescriptions during pregnancy. Outcome was recognized as an ASD diagnosis by the British Columbia Autism Assessment Network by December 2016. After analyzing the data, the authors discovered a small to moderate ASD risk associated with gestational antibiotic exposure. Additionally, the team observed that the most significant risk for ASD was associated with antibiotic exposure lasting longer than 14 days. The authors pointed out that previous research revealed an increased risk of ASD when the antibiotic exposure occurred during the second and third trimesters. However, their study identified the highest risk in the first and second trimester exposure. The researchers observed roughly the same ASD risk for both vaginal and cesarean deliveries and a lower risk associated with combined prenatal and labor and delivery antibiotic exposure. They pointed to evidence that exhibits differences between microbial profiles of infants by mode of delivery and exposure to intrapartum antibiotics, with differences in bacterial abundance and diversity. Consequently, the authors suggest that an altered microbial colonization at birth, and its potential impact on infant neurodevelopment, is not a likely contributor to the association between prenatal antibiotic exposure and ASD. They propose that the risk observed in the first and second trimesters could be due to the susceptible periods for metabolic programming by the maternal microbiome. Ultimately, the authors concluded that their findings need more research to be considered clinically significant.
