Human spontaneous labor without histologic chorioamnionitis is characterized by an acute inflammation gene expression signature

Objective: The purpose of this study was to identify which biological processes may be involved in normal labor. Study design: Transcriptional profiles for chorioamniotic membranes (n = 24) and blood (n = 20) were generated from patients at term with no labor (TNL) and in labor (TIL). Results: Expression of 197 transcripts (P ≤ .02) differentiated TIL and TNL chorioamniotic membrane samples. Gene Ontology analysis indicated that TIL samples had increased expression of multiple chemokines and transcripts associated with neutrophil and monocyte recruitment. Microarray results were verified using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) with independent samples. Transcriptional profiles from blood RNA revealed no Gene Ontology category enrichment of discriminant probe sets. Conclusion: Labor induces gene expression changes consistent with localized inflammation, despite the absence of histologically detectable inflammation.