Fig. 5

The validation of candidate markers and the performance of predictive models. A Blood sample collection timelines in the validation cohort. triangles: GA at blood collection, squares: GA at delivery. B Means ± SD for the relative expression level of ARHGEF28 validated using RT-qPCR. ***p-value < 0.001 (Mann–Whitney U-test). C The correlation of the relative expression level of ARHGEF28 with gestational age. D Receiver operating characteristic (ROC) curve representing prediction of preterm birth by the gene ARHGEF28 across the training dataset and testing dataset using SVM algorithm. E Altered in the relative expression level of ARHGEF28 in the three subgroups including early preterm, late preterm, and term. F ROC curves representing prediction of late preterm by the gene ARHGEF28 across the training dataset and testing dataset using SVM algorithm