Influence of vaginal microbiota on the pathophysiology of microbial-associated intra-amniotic inflammation and “sterile” inflammation in women with preterm labor with intact membranes and women with preterm prelabour rupture of the membranes

Background: Sequencing of 16S rRNA gene emerges to better understand the influence of microbiome on spontaneous preterm birth (sPTB). There is a few data regarding its influence on the infectious/inflammatory physiopathology of sPTB. According to the amniotic fluid (AF) information of infection/inflammation (IAI), four phenotypes of women have been defined: microbial-associated IAI, “sterile” IAI, colonization and a “negative” phenotype, without infection or IAI. The influence of vaginal microbiota on the physiopathology of these phenotypes remains unknown in women with preterm labor (PTL) and preterm prelabour rupture of membranes (PPROM).  Hypothesis: -In women with PTL and PPROM, the vaginal microbiota differs among the different infectious/inflammatory phenotypes. -Women with PTL or PPROM present a different vaginal microbiota than those without symptoms delivered at term. Objectives: -To evaluate, in women with PTL and PPROM, whether vaginal microbiota differs among the different infectious/inflammatory phenotypes. -To evaluate whether vaginal microbiota differs among women with symptoms of PTL and PPROM and women without symptoms. Methodology: Two phases of the study: Study 1: Observational prospective cohort study including women admitted with PTL or PPROM <34.0 weeks with an amniocentesis to rule out infection/IAI. Infection will be diagnosed based on AF cultures and AF PCR of 16S rRNA gene and IAI based on AF interleukin (IL)-6 levels. Study 2: a case-control study comparing women with PTL and PPROM (cases) and a control group of women without symptoms who delivered at term matched by gestational age at vaginal sampling. Sequencing of 16S rRNA gene in the vaginal fluid will be performed using Illumina MiSeq® System. Expected results: In PTL and PPROM, we expect to find differences on the vaginal microbiota among the different infectious/inflammatory phenotypes and between women with symptoms of PTL or PPROM and women without symptoms delivered at term.