Specific Aim 3. Integrated host genomics, metatranscriptomics and metabonomics data will reveal molecular mechanisms and networks underlying preterm birth in a limited subset of samples. Methods: We will interrogate and integrate our concomitantly acquired clinical metadata, microbial and host gene expression data (RNA-Seq metatranscriptomics), and metabonomics profiling with advanced computational and biostatistical approaches. We will be guided in our choice of subjects by our data from Aims 1 and 2.