Preterm birth risk: vaginal microbiota in pregnant women with and without short cervix

The pregnant women 68 with singleton gestation and a cervical length =25 mm and 28 pregnant women without a short cervix >25 mm in the second or early third trimester (23–32 weeks' gestation) were enrolled. Vaginal secretions were collected by inserting a swab then the bacterial 16S rRNA gene was amplified using a primer set specific for the V3–V4 hypervariable regions. he vaginal microbiome of our cohort of pregnant women was mainly represented by bacteria belonging to the phylum Firmicutes and presenting percentage variations in the Actinobacteriota, Proteobacteria and Bacteroidota phyla. Alpha-diversity metric (observed) was significantly higher in control group. Specific taxonomic features were associated to short cervix condition, among these, the genera Staphylococcus, Pseudomonas, Brevundimonas, Pseudoxanthomonas and Tabrizicola. Therefore, specific sequence variants association was also depicted, in particular ASV_12 and ASV_8 assigned to Lactobacillus genus were significantly enriched in control and short cervix groups respectively. The study highlights an association between cervical length and vaginal bacterial communities and this further defines the importance of studying the vaginal microbiota to understand the associated clinical conditions.