Table 2.

Studies investigating DNA methylation in whole blood during gestational diabetes mellitus.

Author	Study Design	Country	Detection Method	Main Finding
Dias et al., 2018 [114]	63 GDM and 138 controls (~26 weeks gestation)	South Africa	Global DNA methylation using MDQ1 Imprint DNA Quantification Kit *	No difference in global DNA methylation between women with or without GDM. Global DNA methylation was associated with obesity and serum adiponectin concentrations.
Enquobahrie et al., 2015 [116]	6 women with 2 consecutive pregnancies with and without GDM (<20 weeks gestation)	United States	Illumina HumanMethylation27 BeadChip	17 CpG sites were hypomethylated and 10 CpG sites were hypermethylated in relation to GDM status
Kang et al., 2017 [115]	8 GDM and 8 controls (end of pregnancy)	Taiwan	Illumina Infinium HumanMethylationEPIC BeadChip	200 differentially methylated CpGs corresponding to 151 genes identified in women with GDM compared to controls
Kang et al., 2018 [118]	8 GDM and 24 controls (end of pregnancy)	Taiwan	MethyLight qRT-PCR assay	Decreased methylation of IL-10 during GDM, which was associated with increased serum IL-10 concentrations
Wu et al., 2018 [117]	11 GDM and 11 controls (12–16 weeks gestation)	United Kingdom	Illumina HumanMethylation450 BeadChip (450K) array and bisulfite pyrosequencing	100 differentially methylated CpGs corresponding to 66 genes were identified. Differential DNA methylation at 5 CpGs were validated in 8 of the 11 GDM women

qRT-PCR—quantitative real-time PCR; CpG—cytosine–phosphate–guanine; IL-10—interleukin-10; GDM—gestational diabetes mellitus. * Sigma-Aldrich. St. Louis, USA.