Table 3. Prevalence of gestational diabetes mellitus (GDM)and the optimal cut-off points of glycated hemoglobin (HbA1c) for GDM in different age groups.

Age group (years)	Number of subjects	Prevalence of GDM (%)	HbA1c-thresholds, % [mmol/mol]	Sensitivity, %	Specificity, %	Positive predictive value (PPV), %	Negative predictive value (NPV), %	Youden index
20–24	803	7.472	4.9 [30]	71.7	61.2	13.0	96.4	0.329
25–29	7,200	14.028	5 [31]	56.1	68.7	22.6	90.6	0.248
30–34	7,452	19.740	5 [31]	61.1	64.4	29.5	87.1	0.255
35–39	3,204	25.780	5 [31]	61.6	58.2	33.9	81.4	0.198
≥40	588	31.973	5 [31]	70.2	55.3	42.4	79.8	0.255