Infantile Pyloric Stenosis Associated with Macrolide Antibiotic Use Interview with:
Marie Lund MD, PhD student
Department of Epidemiology Research
København S | Denmark What are the main findings of the study?

Dr. Lund: We found macrolide use in infants to be associated with a 30-fold increased risk of infantile hypertrophic pyloric stenosis (IHPS) with use during the first two weeks after birth and a lower, but significantly increased threefold risk with use during days 14 to 120. Similarly, there was a more than three-fold increased risk of IHPS associated with maternal macrolide use during the first two weeks after birth, but no increased risk with use thereafter. Finally, we found a possible modest association between maternal macrolide use during weeks 28 to birth and infantile hypertrophic pyloric stenosis. What should clinicians and patients take away from your report?

Dr. Lund: Macrolide use in young infants was strongly associated with infantile hypertrophic pyloric stenosis and should only be administered if potential treatment benefits outweigh the risk. Although the associations with infantile hypertrophic pyloric stenosis were less strong for maternal macrolide use when infants were less than 2 weeks old and for infant use during days 14 to 120 after birth, they should still be considered when treatment decisions are made. What recommendations do you have for future research as a result of this study?

Dr. Lund: The literature, including our study, is still uncertain as to whether an association exists between maternal macrolide use during late pregnancy and subsequent IHPS in the child. Although an increase in risk, if any, would be small in terms of absolute numbers, there are a number of studies published now and I think it might be worthwhile addressing this data in a meta-analysis. Most studies, including ours, implicate erythromycin, however, we do still not know whether reported associations represent a class effect and can be attributed to all macrolides or whether there are differences between individual agents. Again, collaborative studies are most probably the best approach given sample size requirements. Finally, our study was the first to report a significant association between maternal macrolide use after birth and IHPS; to confirm and expand on these findings this should be investigated in an independent population.


Link to the published study:

Lund M ,Pasternak B ,Davidsen RB ,Feenstra B ,Krogh C ,Diaz LJ ,et al. Use of macrolides in mother and child and risk of infantile hypertrophic pyloric stenosis: nationwide cohort study. BMJ 2014;348:g1908