| Characteristics | Positive GCT (cases) n = 441 (%) | Normal GCT (controls) n = 441 (%) | p value |
| Maternal age (years) | |||
| Mean ± sd | 28.6 ± 6.1 | 26.0 ± 5.5 | <0.000a |
| Missing | 0 | 0 | |
| Gravida | |||
| 1 | 107 (24.4) | 117 (26.5) | 0.093 |
| Missing | 2 | 0 | |
| Body mass index (kg/m2) | |||
| <18.5 | 6 (1.5) | 10 (2.5) | 0.007 |
| 18.5 - 24.9 | 106 (26.2) | 139 (34.2) | |
| 25 - 29.9 | 119 (29.5) | 128 (31.5) | |
| ≥30 | 173 (42.8) | 129 (31.8) | |
| Missing | 37 | 35 | |
| Smoking | 148 (33.7) | 118 (26.8) | 0.025 |
| Missing | 2 | 0 | |
| Previous gestational diabetes mellitus | 9 (2.7) | 2 (0.6) | 0.064b |
| Missing | 108 | 119 | |
| Previous hypertension | 40 (9.1) | 35 (7.9) | 0.532 |
| Missing | 2 | 0 | |
| Ethnicity | |||
| Caucasian | 344 (78.0) | 355 (80.5) | 0.481 |
| ATSI* | 18 (4.1) | 22 (5.0) | |
| Samoan | 50 (11.3) | 45 (10.2) | |
| Asian | 12 (2.7) | 10 (2.3) | |
| Others | 17 (3.9) | 9 (2.0) | |
| Marital status | |||
| Never married | 58 (13.3) | 82 (18.9) | 0.075 |
| Married/de facto | 371 (84.9) | 344 (79.1) | |
| Divorced/separated | 8 (1.8) | 9 (2.1) | |
| Missing | 4 | 6 |