Al-Memar M, Bobdiwala S, Fourie H, et al. - Researchers sought to describe vaginal bacterial composition in early pregnancy and examined how it is related to first and second trimester miscarriages. They conducted a nested case-control study of 161 pregnancies at Queen Charlotte’s and Chelsea Hospital, Imperial College Healthcare NHS Trust, London. Of these, 64 resulted in first-trimester miscarriage, 14 in second-trimester miscarriage and 83 term pregnancies. First trimester miscarriage were noted to be correlated with reduced prevalence of Lactobacillus spp.-dominated vaginal microbiota classified using hierarchical clustering analysis (65.6 vs 87.7%), higher alpha diversity (mean Inverse Simpson Index 2.5 vs 1.5 ) and higher richness [25.1 (18.5–31.7) vs 16.7 (13.4–20)), compared with viable pregnancies. This was observed independent of vaginal bleeding and was noted before the first-trimester miscarriage diagnosis. Compared with a missed miscarriage, incomplete/complete miscarriage was noted to be associated with higher proportions of Lactobacillus spp.-depleted communities. Miscarriage and term pregnancies were similar in terms of early pregnancy vaginal bacterial stability.