Table 1.
Characteristics of the study population by GDM.
| Factor | No GDM (n = 35,855) |
GDM (n = 8324) |
p * |
|---|---|---|---|
| Age, mean years (SD) | 28.6 (3.9) | 29.7 (4.2) | <0.001 |
| Age Categories, n (%) | <0.001 | ||
| <25 | 5129 (14) | 729 (9) | |
| 25 to <30 | 17,495 (49) | 3567 (43) | |
| 30 to <35 | 10,482 (29) | 2851 (34) | |
| ≥35 | 2749 (8) | 1177 (14) | |
| Parous, n (%) | 10,777 (30) | 2778 (33) | <0.001 |
| Maternal Height, mean cm (SD) | 162.0 (4.6) | 161.6 (4.7) | <0.001 |
| Maternal Height Categories, n (%) | <0.001 | ||
| <160 | 5503 (24) | 1469 (27) | |
| 160 to <165 | 10,614 (46) | 2444 (44) | |
| 165 to <170 | 5631 (24) | 1258 (23) | |
| ≥170 | 1577 (7) | 336 (6) | |
| Missing | 12,530 (35) | 2817 (34) | |
| Pre-pregnancy BMI kg/m2, mean (SD) | 21.8 (3.1) | 23.0 (3.3) | <0.001 |
| Pre-pregnancy BMI Categories, n (%) | <0.001 | ||
| Underweight (<18.5) | 2894 (8) | 352 (4) | |
| Normal (18.5 to <25) | 17,141 (48) | 3768 (45) | |
| Overweight (25 to <30) | 2841 (8) | 1168 (14) | |
| Obese (≥30) | 369 (1) | 191 (2) | |
| Missing | 12,610 (35) | 2845 (34) | |
| Gestational Length, mean weeks (SD) | 40.1 (1.4) | 39.8 (1.5) | <0.001 |
| Male Fetus, n (%) | 18,503 (52) | 4337 (52) | 0.41 |
| Birth Length, mean cm (SD) | 50.1 (1.4) | 50.0 (1.6) | 0.28 |
| Birth Weight, mean g (SD) | 3384 (445) | 3418 (485) | <0.001 |
| Birth Weight Categories, n (%) | <0.001 | ||
| <2500 | 869 (3.5) | 247 (4.2) | |
| 2500 to <4000 | 20,916 (84.9) | 4771 (81.0) | |
| ≥4000 | 2848 (11.6) | 872 (14.8) | |
| Missing | 11,222 (31) | 2434 (30) |
* continuous data are presented as mean (SD) and compared using Student t test; categorical variables are presented as frequency, n (%), and compared using x2 tests.