Fig. 7

Representation of overlap in differentially expressed genes across the most commonly studied tissues, phenotypes, and tissues & phenotypes. Studies are represented as distinct wedges in the outermost track, colored by phenotype and sized by number of genes reported. Genes that show a high degree of overlap across studies (4 or more placenta, PE, or PE in placenta studies; 4 or more myometrium, labor, or labor in myometrium studies; 4 or more fetal membranes studies; or 2 or more PPROM or PPROM in fetal membranes studies) appear as black links connecting each study reporting the gene. In general, the scarcity of links illustrates the considerable lack of overlap in the genes identified as differentially expressed across PTB studies. a Representation of overlap in differentially expressed genes across the most commonly studied tissues. Studies of placenta, myometrium, and fetal membranes, the three most commonly studied tissues, focused on a total of 25 distinct phenotypes with PE dominating placental research, labor dominating myometrial research, and PPROM dominating fetal membranes research. b Representation of overlap in differentially expressed genes across the most commonly studied phenotypes. PE was studied across 4 distinct gestational tissues (placenta, decidua, basal plate, and maternal blood), labor was studied across 4 distinct gestational tissues (myometrium, fetal membranes, placenta, and cervix), and PPROM was studied across only 1 distinct gestational tissue (fetal membranes). c Representation of overlap in differentially expressed genes across the most commonly studied tissue and phenotype combinations. The most studied combinations were PE in placenta (n = 23), labor in myometrium (n = 9), and PPROM in fetal membranes (n = 3). Examination of PE in placenta studies identified 16 genes that were present in 4 or more studies, examination of labor in myometrium studies identified 15 genes that were present in 4 or more studies, and examination of PPROM in fetal membranes studies identified 6 genes that were present in 2 or more studies