Table 2.
Variation of birth weight, total GWG and mean weight gain per week with GWG category in each of the four pre-pregnancy BMI groups.
| BMI | GWG category according to IOM | N (%) | Birth weight (g) | Total gestational weight gain (kg) | Mean weight gain per week (kg) |
|---|---|---|---|---|---|
| Underweight | Inadequate | 25 (26.0%) | 3076 ± 272* | 10.49 ± 1.49* | 0.27 ± 0.04* |
| Adequate | 48 (50.0%) | 3278 ± 312* | 15.10 ± 1.58* | 0.38 ± 0.04* | |
| Excessive | 23 (24.0%) | 3478 ± 353* | 24.43 ± 7.96* | 0.62 ± 0.22* | |
| Normal weight | Inadequate | 136 (24.4%) | 3184 ± 464* | 8.95 ± 2.04* | 0.23 ± 0.05* |
| Adequate | 244 (43.7%) | 3441 ± 416† | 13.86 ± 1.39* | 0.35 ± 0.04* | |
| Excessive | 178 (31.9%) | 3479 ± 387† | 20.18 ± 3.76* | 0.51 ± 0.10* | |
| Overweight | Inadequate | 18 (13.4%) | 3391 ± 203 | 5.26 ± 1.18* | 0.13 ± 0.03* |
| Adequate | 44 (32.8%) | 3418 ± 343 | 9.25 ± 1.42* | 0.24 ± 0.04* | |
| Excessive | 72 (53.7%) | 3549 ± 471 | 16.47 ± 3.65* | 0.42 ± 0.09* | |
| obese | Inadequate | 7 (15.9%) | 3593 ± 514 | 2.97 ± 1.59* | 0.08 ± 0.04* |
| Adequate | 17 (38.6%) | 3382 ± 729 | 7.22 ± 1.55* | 0.19 ± 0.04* | |
| Excessive | 20 (45.5%) | 3503 ± 707 | 13.13 ± 3.98* | 0.34 ± 0.10* | |
| Interaction effects‡ | 1.73 | 3.23§ | 2.85|| |
Data presented as n (%) or mean ± standard deviation. BMI, body mass index; GWG, gestational weight gain; IOM, Institute of Medicine. *P < 0.05 vs. both the other GWG groups; †P < 0.05 vs. inadequate GWG group; ‡the F-value for the interaction effects; §interaction effect of BMI*GWG on total gestational weight gain, P < 0.05; ||interaction effect of BMI*GWG on mean weight gain per week, P < 0.05.