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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

From: Are women who quit smoking at high risk of excess weight gain throughout pregnancy?

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)
  1. Bold values are above the recommended IOM range
  2. Abbreviation(s): BMI body mass index, IOM Institute of Medicine