As depicted in Fig. 2 and Supplementary Table 2, the expression of PD-1 on Tregs in pregnant women with GDM during the third trimester (9.58% ± 2.47%) was significantly lower than that in healthy pregnant women in the third trimester (16.31% ± 2.53%, P < 0.01). This evidence concerns the gene PDCD1 and gestational diabetes.