categories derived from the Metropolitan Life Insurance tables. Second, and more importantly, the new guidelines include a specific, relatively narrow range of recommended gain for obese women.
These new guidelines should be considered in the context of data on women’s reported GWG. Data from several large groups of women indicate that the mean gains of underweight women fall within the new guidelines, but some normal weight women may exceed these new guidelines and a majority of overweight or obese women will likely exceed them. These data provide a strong reason to assume that interventions will be needed to assist women, particularly those who are overweight or obese at the time of conception, in meeting the guidelines. These interventions may need to occur at both the individual and community levels and may need to include components related to both improved dietary intake and increased physical activity.
The committee intends that the guidelines shown in Table S-1 be used in concert with good clinical judgment as well as a discussion between the woman and her care provider about diet and exercise. If a woman’s GWG is not within the proposed guidelines, clinicians should consider other relevant clinical evidence, modifiable factors that might be causing excessive or inadequate gain, and information on the nature of excess GWG (e.g., fat or edema) as well as both the adequacy and consistency of fetal growth before suggesting that a woman modify her pattern of weight gain.
The IOM (1990) report recommended that women of short stature (< 157 cm) gain at the lower end of the range for their prepregnant BMI. The committee was unable to identify evidence sufficient to continue to support a modification of GWG guidelines for women of short stature. Although women of short stature had an increased risk of emergency cesarean delivery, this risk was not modified by GWG. Women of short stature did not have an increased risk of having a small-for-gestational age (SGA) or large-for-gestational age (LGA) infant or of excessive postpartum weight retention over taller women.
Evidence available since the IOM (1990) report is also insufficient to continue to support a modification of the GWG guidelines for adolescents (< 20 years old) during pregnancy. The committee also determined that prepregnancy BMI could be adequately categorized in adolescents by using