Table 3. Associations of Prepregnancy Weight and Weight Gain Within Each Gestational Interval With Infant Birth Weight.
| Model | Maternal Weight Variable | Infant Birth Weight, g, β (95% CI)a | |
|---|---|---|---|
| Analyses With Observed Data | Analyses With Multiple Imputation Data | ||
| 1 | Prepregnancy weight | 15.2 (8.7 to 21.7)b | 15.6 (11.5 to 19.8)b |
| Weight gain from pregravid to 14 wk | 13.6 (3.2 to 24.1)b | 13.2 (5.5 to 20.9)b | |
| 2 | Prepregnancy weight | 14.4 (8.0 to 21.7)b | 14.4 (10.3 to 18.4)b |
| Weight gain from 14 to 18 wk | 26.1 (3.8 to 48.4)b | 22.0 (5.6 to 38.3)b | |
| 3 | Prepregnancy weight | 13.9 (8.0 to 19.7)b | 14.0 (9.9 to 18.0)b |
| Weight gain from 19 to 23 wk | 11.3 (−8.9 to 31.5) | 15.6 (−5.2 to 27.8) | |
| 4 | Prepregnancy weight | 12.5 (6.4 to 18.6)b | 13.0 (7.0 to 19.1)b |
| Weight gain from 24 to 28 wk | 15.3 (−4.1 to 34.8) | 15.6 (−3.6 to 34.8) | |
| 5 | Prepregnancy weight | 15.3 (9.2 to 21.3)b | 15.3 (9.3 to 21.3)b |
| Weight gain from 29 to 30 wk | −1.4 (−26.6 to 23.8) | −2.3 (−27.2 to 22.5) | |
| 6 | Prepregnancy weight | 24.7 (16.2 to 33.1)b | 25.0 (16.7 to 33.3)b |
| Weight gain from 31 to 32 wk | −1.0 (−39.9 to 37.9) | −2.0 (−40.0 to 35.9) | |
| 7 | Prepregnancy weight | 21.4 (12.8 to 30.2)b | 21.5 (12.8 to 30.1)b |
| Weight gain from 33 to 34 wk | 15.6 (−39.6 to 70.8) | 13.8 (−40.4 to 68.1) | |
| 8 | Prepregnancy weight | 15.7 (8.0 to 23.4)b | 15.5 (7.9 to 23.0)b |
| Weight gain from 35 to 36 wk | 4.6 (−32.9 to 42.0) | 4.8 (−32.0 to 41.5) | |
| 9 | Prepregnancy weight | 17.5 (11.4 to 23.8)b | 14.3 (10.2 to 18.3)b |
| Weight gain from 37 to 38 wk | 7.9 (−18.9 to 34.7) | 16.9 (−8.1 to 41.8) | |
| 10 | Prepregnancy weight | 16.5 (10.3 to 22.7)b | 14.1 (10.0 to 18.2)b |
| Weight gain from 39 to 40 wk | −2.0 (−34.8 to 30.9) | 2.3 (−30.1 to 36.8) | |
a
β represents an estimate of linear regression coefficient, representing the change in infant birth weight (grams) when the indicated maternal weight variable changes by 1 kg. All models are adjusted for prepregnancy weight, weight gain within each interval, total length of gestation, and infant sex.
b
The 95% CI did not cross 0, indicating that there is a significant association between the indicated maternal weight variable and infant birth weight.