Global CpG hypomethylation in cord blood cells is associated with maternal preeclampsia. (A) 3D Principal Components Analysis (PCA) of the methylation M-values from cord blood samples. Preeclampsia-associated cases are shown in red, while controls are in blue; PCA1, PCA2, and PCA3 denote principal components 1, 2, and 3, respectively. The two groups are clearly separated when viewed using the first three principal components. (B) ANOVA plot of clinical factors using the methylation M-values in cord blood samples. Averaged ANOVA F-statistics are calculated for potential confounding factors, including preeclampsia, maternal age, gravida, parity, and baby gender. (C) Volcano plot of all CpG methylation M-values. The y-axis of the negative log10 transformation of the P values obtained from differential methylation analysis of the CpG sites is plotted against the x-axis of the difference in the average M-values between cases and controls. The dashed red line marks the α = 0.05 significance threshold after Benjamini-Hochberg correction of multiple hypothesis tests (MHT), whereas the dashed black line marks the unadjusted α = 0.05 significance threshold.