Description:This project characterized the microbiomes of pregnant women to gauge microbiome effects on risk of preterm birth (PTB). The project followed 1,527 women longitudinally through pregnancy and involved the collection of 206,437 samples, including maternal vaginal, buccal, rectal, skin and nares swabs, blood, urine, and birth products, as well as infant cord and cord blood, meconium and first stool, buccal, skin and rectal swabs. Subsets of these specimens underwent 16S rRNA gene taxonomic analysis, metagenomic and metatranscriptomic sequencing, cytokine profiling, lipidomics analysis, and bacterial genome analysis.