outcomes and their frequency in the population. To develop estimates of risk and frequency, the committee used data from the published literature and from additional, commissioned analyses (see below).

The committee considered the incidences, long-term sequelae, and baseline risks of several potential outcomes associated with GWG (additional information about these outcomes appears in Appendix G). Postpartum weight retention, cesarean delivery, gestational diabetes mellitus (GDM), and pregnancy-induced hypertension or preeclampsia emerged from this process as being the most important maternal health outcomes. The committee removed preeclampsia from consideration because of the lack of sufficient evidence that GWG was a cause of preeclampsia and not just a reflection of the disease process. The committee also removed GDM from consideration because of the lack of sufficient evidence that GWG was a cause of this condition. Postpartum weight retention and, in particular, unscheduled primary cesarean delivery were retained for further consideration.

Measures of size at birth (e.g., small-for-gestational age [SGA] and large-for-gestational age [LGA]), preterm birth and childhood obesity emerged from this process as being the most important infant health outcomes. The committee recognized that both SGA and LGA, when defined as < 10th percentile and > 90th percentile of weight for gestational age, respectively, represent a mix of individuals who are appropriately or inappropriately small or large. In addition, the committee recognized that being SGA was likely to be associated with deleterious outcomes for the infant but not the mother, while being LGA was likely to be associated with consequences for both the infant and the mother (e.g., cesarean delivery). The committee addressed this mix of outcomes in the approach used to develop its recommendations.

Importantly, although the Institute of Medicine report (IOM, 1990) recognized a trade-off between maternal and child health was recognized as a possible consequence of changing the weight-gain guidelines, evaluation of that trade-off was not possible with the data then available. This committee made evaluating this trade-off a central element of its process to develop new guidelines while recognizing that, although the available data have increased, they are still less than fully adequate for this purpose. In making its recommendations, the committee also sought to recognize unintended consequences and to develop guidelines that are both feasible and potentially achievable. It is important to note that these guidelines are intended for use among women in the United States. They may be applicable to women in other developed countries; however, they are not intended for use in areas of the world where women are substantially shorter or thinner than American women or where adequate obstetric services are unavailable.

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