Table 1. Population characteristics according to GDM in second pregnancy.
A population-based cohort study (n = 24,198), The Medical Birth Registry of Norway, 2006–2014.
| GDM in Second Pregnancy | ||||
|---|---|---|---|---|
| Yes | % | Total | p-value* | |
| BMI in first pregnancy (kg/m2) | ||||
| <18.5 | 13 | 1.2 | 1,065 | <0.001 |
| 18.5–24.9 | 169 | 1.1 | 16,052 | |
| 25–29.9 | 142 | 3.0 | 4,812 | |
| ≥30.0 | 115 | 5.1 | 2,269 | |
| BMI in second pregnancy (kg/m2) | <0.001 | |||
| <18.5 | 5 | 0.6 | 897 | |
| 18.5–24.9 | 120 | 0.8 | 14,812 | |
| 25–29.9 | 137 | 2.5 | 5,534 | |
| ≥30.0 | 177 | 6.0 | 2,955 | |
| Gestational weight gain in second pregnancy (kg) | <0.001 | |||
| <−0.1 | 4 | 4.0 | 100 | |
| 0–7.9 | 57 | 4.5 | 1,274 | |
| 8–15.9 | 104 | 1.6 | 6,489 | |
| ≥16.0 | 50 | 1.2 | 4,215 | |
| Missing | 224 | 1.8 | 12,120 | |
| Maternal age (years) | <0.001 | |||
| <25 | 32 | 1.1 | 3,014 | |
| 25–29 | 142 | 1.7 | 8,476 | |
| 30–34 | 151 | 1.7 | 8,987 | |
| ≥35 | 114 | 3.1 | 3,721 | |
| Maternal country of birth | <0.001** | |||
| Nordic | 315 | 1.6 | 19,828 | |
| Non-Nordic | 121 | 2.9 | 4,215 | |
| Missing | 3 | 1.9 | 155 | |
| Maternal education (years) | 0.034 | |||
| <11 | 73 | 2.1 | 3,460 | |
| 11–13 | 124 | 2.0 | 6,323 | |
| ≥14 | 225 | 1.6 | 13,678 | |
| Missing | 17 | 2.3 | 737 | |
| Smoking | 0.516** | |||
| No | 370 | 1.8 | 20,616 | |
| Yes | 15 | 1.5 | 990 | |
| Missing | 54 | 2.1 | 2,592 | |
| Interpregnancy interval (months) | <0.001 | |||
| <12 | 70 | 1.5 | 4,806 | |
| 12 to <24 | 151 | 1.5 | 10,342 | |
| 24 to <36 | 114 | 2.0 | 5,811 | |
| ≥36 | 104 | 3.2 | 3,210 | |
| Missing | 0 | 0.0 | 29 | |
*Chi-square test for linear trend.
**Pearson Chi square.
BMI, Body Mass Index; GDM, Gestational Diabetes Mellitus