Table 1 Maternal characteristics of 1394 southeastern Finnish women with singleton pregnancies divided into two groups based on 2 h 75 g oral glucose tolerance test results at 12 to 16 weeks’ gestation (OGTT1): women with one or more plasma glucose concentrations > 90th percentile and women with all plasma glucose concentrations (0 h, 1 h, and 2 h) ≤ 90th percentile

n = 1086

n = 308

Age (years), mean (SD)

29 (5)

31 (5)

< 0.001

Nulliparous, n (%)

580 (53)

127 (41)

< 0.001

Previous history of GDM, n (%)

44 (4)

74 (24)

< 0.001

Family history of type 2 diabetes, n (%)

450 (41)

149 (48)

0.030

Smoking during pregnancy, n (%)

112 (10)

31 (10)

0.87

Polycystic ovary syndrome, n (%)

58 (5)

22 (7)

0.23

Pre-gestational weight (kg), mean (SD)

68 (14)

78 (18)

< 0.001

Height (cm), mean (SD)

166 (6)

165 (6)

0.063

Pre-gestational BMI (kg/m2), mean (SD)

24.7 (4.6)

28.5 (6.5)

< 0.001

Waist circumference* (cm), mean (SD)

83 (10)

92 (12)

< 0.001

Waist-to-height ratio, mean (SD)

0.50 (0.06)

0.56 (0.08)

< 0.001

Early-pregnancy HbA_1c* (mmol/mol), mean (SD)

33.1 (3.2)

35.1 (3.5)

< 0.001

Fasting insulin** (mU/L), mean (SD)

7.9 (6.8)

12.0 (12.0)

< 0.001

Insulin resistance index (HOMA-IR), mean (SD)

1.69 (1.45)

2.77 (2.79)

< 0.001

Pharmacologically-treated GDM, n (%)

9 (1)

43 (14)

< 0.001