Liu Y, Li X, Zhu B, et al. - Researchers sought to ascertain if a microbial signature could be identified in the mid-trimester amniotic fluid of patients who subsequently had normal pregnancy outcomes. From 37 pregnancies (5 twin and 32 singletons), they collected 42 amniotic fluid samples during genetic amniocentesis in the mid-trimester for this prospective cohort study. No bacteria in cultures were identified under anaerobic or aerobic conditions or genital mycoplasmas from any of the amniotic fluid samples. No greater copy numbers of 16S rRNA gene were identified in amniotic fluid samples vs negative controls in quantitative PCR. 16S rRNA gene sequencing revealed no significant difference in the microbial richness or community structures between amniotic fluid and negative controls.