Report of a special panel on desired prenatal weight gains for underweight and normal weight women.

A major challenge facing the health care system is to improve the distribution of infant birth weights. Prenatal weight gain and prepregnancy weight status are two of the major factors that influence infant birth weight. These are independently and linearly related to birth weight. It is believed by many that the distribution of infant birth weights may be improved by implementing prenatal weight gain goals that optimize the relationship between prepregnancy weight status and infant birth weight. The panel considered prenatal weight gains for underweight and normal weight women that correspond to the delivery of infants with birth weights within a desired range. The panel identified (a) the desired range of birth weights as 3,500 to 3,999 grams; (b) for underweight women starting pregnancy, a prenatal weight gain of 30 to 35 pounds (lb), plus the prepregnancy weight deficit for the height of the woman; and (c) for normal weight women starting pregnancy, a gain of 30 to 35 lb. The report summarizes the scientific rationales for the conclusions, as well as the results of deliberations on potential risks to maternal health of the suggested weight gains.