Microbial transcriptome in vaginal fluid at midgestation: association with spontaneous preterm delivery

It is widely accepted that intrauterine infection and inflammation are important causative factors of spontaneous PTD and are often hypothesized to be secondary to pathogen ascension from the vagina. Therefore, multiple studies have tried to characterize the relationship between the cervicovaginal microbiome and spontaneous PTD, with divergent results. An important factor seems to be the difference in ethnicity, especially between women who identify themselves as African American and women who identify themselves as White. Most of the studies have applied an DNA-based assessment of bacterial community composition which provide information on the taxonomic composition of the bacterial communities but not to which extent they are active members of the microbiome. The objective of this study was to with a transcriptomic approach using high throughput sequencing, assess whether there are differences in the active vaginal microbiome (metatranscriptome) in the second trimester in women with subsequent spontaneous PTD compared with term delivery in a mainly White population. Samples from 48 women delivering preterm and 96 women delivering at term were sequenced and analyzed.