As depicted in Fig. 3 and Supplementary Table 2, the expression of PD-1 on Tregs in pregnant women with GDM during the third trimester (14.45% ± 3.34%) was significantly lower than that in healthy pregnant women in the third trimester (26.24% ± 3.91%, P < 0.01). This evidence concerns the gene PDCD1 and gestational diabetes.