FIGURE 2-2 Distribution of BMI from 1999 to 2004 among U.S. nonpregnant women 12 to 44 years of age using the IOM^a (1990) and the WHO^b BMI cutoff points.

^aIOM (1990) BMI categories are underweight, < 19.8 kg/m²; normal, 19.8-26.0 kg/m²; overweight, 26.1-29.0 kg/m²; obese, > 29 kg/m².

^bWHO BMI categories are underweight, < 18.5 kg/m²; normal, 18.5-24.9 kg/m²; overweight, 25.0-29.9 kg/m²; obese, ≥ 30 kg/m².

SOURCE: Personal communication, A. Branum, CDC, Hyattsville, Maryland, April 15, 2008.

pregnancy mothers of term, of < 16 pounds and > 40 pounds both increased (Figure 2-3). Weight gain within the broad recommended range (16 to 40 pounds) (IOM, 1990) declined slowly during this 15-year period. Unfortunately, the standard birth certificate lacks data on maternal prepregnancy weight and height. Thus, data from this source cannot provide information about GWG relative to prepregnant BMI category. Additionally, the data on prepregnancy weight was self-reported and therefore more variable than clinical measures. The loss in precision and the degree of bias due to self-reporting must be taken into account when interpreting those data.

There were some important differences in low and high gains among women in the different racial/ethnic and age groups. Specifically, the greatest increase in the proportion of women with a weight gain > 40 pounds from 1990 to 2005 was among white women (Figure 2-4). In 2005, adolescents (< 20 years old) were more likely to gain excessive weight during