Table 1.

The 2009 Institute of Medicine’s recommendations on total weight gain and rate of weight gain for singleton pregnancy

Prepregnancy weight category	Body Mass Index (BMI)	Recommended total weight gain		Rate of weight gain in the second and third trimesters*		Adequate ranges of expected weight gain based on the recommendation**
		Range in kg	Range in lbs	Mean (range) in kg/week	Mean (range) in lbs/week
Underweight	< 18.5	12.5 – 18	28-40	0.51 (0.44-0.58)	1.0 (1.0-1.3)	0.79 – 1.14
Normal weight	18.5-24.9	11.5 – 16	25-35	0.42 (0.35-0.50)	1.0 (0.8-1.0)	0.86 – 1.20
Overweight	25.0-29.9	7.0 – 11.5	15-25	0.28 (0.23-0.33)	0.6 (0.5-0.7)	0.81 – 1.34
Obese	≥ 30.0	5.0 – 9.0	11-20	0.22 (0.17-0.27)	0.5 (0.4-0.6)	0.78 – 1.41

^*Calculations assume that total weight gain in the first trimester (<13 weeks of pregnancy) is 0.5 kg for obese women, 1 kg for overweight women, and 2 kg for normal weight or underweight women.

^**This is calculated by dividing the lower and upper limits of recommended weight gain range by expected weight gain at 40 weeks’ gestation. For example, for underweight women, the expected weight gain at 40 week’s gestation is 15.77 kg (2 kg+[(40-13)*0.51). Thus, the adequate range of expected weight gain based on recommendation for underweight women is (0.79-1.14), where 0.79 = (12.5/15.77).