Intriguing results revealed that peripheral blood cytotoxic NK cell subsets (CD56dimCD16+, CD226+, NKG2D+, CD27-CD11b+) were significantly higher in patients with GDM (90.24 ± 1.02% vs. 84.07 ± 2.12%, P=0.0174; 90.48 ± 1.76 vs. 82.07 ± 3.10, P=0.0447; 88.25 ± 1.42 vs. 83.88 ± 1.56, P=0.0232; 61.27 ± 6.24% vs. 44.35 ± 4.82%, P=0.0456 respectively in Figures 7C–F), suggesting that circulating NK cells in GDM patients were in an abnormally activated state. This evidence concerns the gene KLRK1 and gestational diabetes.