PFKFB3 and preeclampsia: To explore the relationship among cellular hypoxia, oxidative stress‐related DNA methylation of genes and preeclampsia, we combined RNA‐seq data, RRBS methylation data and PE methylation chip data and found that there were 3 genes in the promoter region of H group: ANKRD37, PFKFB3 and LINC01291 (Figure 5A), and there were 3 genes in the genebody region of H group: KCNJ8, HCN1 and TRANK1 (Figure 5B).