To account for advances in our scientific understanding of the determinants and consequences of GWG, the committee developed a modified conceptual framework (Figure S-1). However, it retained the same scientific approach and epidemiologic conventions used previously and discussed in detail in the IOM (1990) report.
The committee began its work by considering appropriate BMI cutoff points and describing trends over time in maternal prepregnancy BMI and GWG among American women. In addition, data were sought on both the determinants and consequences of GWG. The search for such data revealed major gaps in data collection and analysis.
Key Finding S-1: The WHO cutoff points for categorizing BMI have been widely adopted and should be used for categorizing prepregnancy BMI as well.
Key Finding S-2: Currently available data sources are inadequate for studying national trends in GWG, or postpartum weight, or their determinants.
Action Recommendation S-1: The committee recommends that the Department of Health and Human Services conduct routine surveillance of GWG and postpartum weight retention on a nationally representative sample of women and report the results by prepregnancy BMI (including all classes of obesity), age, racial/ethnic group, and socioeconomic status.
Action Recommendation S-2: The committee recommends that all states adopt the revised version of the birth certificate, which includes fields for maternal prepregnancy weight, height, weight at delivery, and gestational age at the last measured weight. In addition, all states should strive for 100 percent completion of these fields on birth certificates and collaborate to share data, thereby allowing a complete national picture as well as regional snapshots.
Research Recommendation S-1: The committee recommends that the National Institutes of Health and other relevant agencies should provide support to researchers to conduct studies in large and diverse populations of women to understand how dietary intake, physical activity, dieting practices, food insecurity and, more broadly, the social, cultural, and environmental context affect GWG.
In developing its recommendations, the committee identified a set of consequences for the short- or long-term health of the mother and the child that are potentially causally related to GWG. These consequences included those evaluated in a systematic review of outcomes of maternal weight gain prepared for the Agency for Healthcare Research and Quality (AHRQ) as well as others based on data from the literature outside the time window considered in that report. To address conflicts and gaps within the available literature, the committee commissioned four additional analyses from