A two-sample Mendelian randomization study

Preterm birth, a major global health issue, may be linked to gut microbiota imbalances, but causality is unclear due to limitations in observational studies. We investigated this relationship using two-sample Mendelian randomization, leveraging GWAS data from the MiBioGen consortium on the microbiota and preterm birth. Selecting single nucleotide polymorphisms associated with the microbiota as instrumental variables, we employed the inverse variance weighting method to estimate causality. We confirmed pleiotropy and excluded outlier SNPs using MR-PRESSO and MR-Egger regression. Cochran's Q test assessed SNPs heterogeneity, and leave-one-out analysis evaluated the influence of individual SNPs on overall estimates. Our results demonstrate a causal link between specific gut microbiota and preterm birth, identifying relevant metabolites. This offers new perspectives on the role of the gut microbiota in preterm birth development.