Table 3.
Total weight gain (kg) in the 1st trimester and weekly rate (kg/week) in the 2nd and 3rd trimesters by smoking status and pre-pregnancy BMI class along with IOM recommendations by BMI class
| BMI | IOM recommended gain | Smoking status | ||
|---|---|---|---|---|
| Women who never smoked | Women who quit smoking | Women who continued to smoke | ||
| 1st trimester (kg) | ||||
| Underweight | 0.5–2.0 | 1.7 (−0.2, 3.5) | 1.0 (−1.0, 3.1) | 3.7 (1.6, 5.7) |
| Normal | 2.0 (1.5, 2.4) | 1.4 (0.4, 2.3) | 4.0 (2.8, 5.2) | |
| Overweight | 2.0 (1.3, 2.6) | 1.3 (0.2, 2.4) | 4.0 (2.7, 5.2) | |
| Obese | 0.7 (−0.1, 1.5) | 0.1 (−1.1, 1.3) | 2.7 (1.5, 3.9) | |
| 2nd and 3rd trimester (kg/week) | ||||
| Underweight | 0.44–0.58 | 0.52 (0.42, 0.62) | 0.62 (0.50, 0.73) | 0.44 (0.33, 0.56) |
| Normal | 0.35–0.50 | 0.51 (0.49, 0.54) | 0.61 (0.56, 0.67) | 0.44 (0.37, 0.50) |
| Overweight | 0.23–0.33 | 0.52 (0.48, 0.55) | 0.62 (0.56, 0.68) | 0.44 (0.37, 0.51) |
| Obese | 0.17–0.27 | 0.38 (0.33, 0.42) | 0.48 (0.41, 0.54) | 0.30 (0.23, 0.37) |
Bold values are above the recommended IOM range
Abbreviation(s): BMI body mass index, IOM Institute of Medicine