Recent issues related to nutrition during pregnancy.

In July 1990, new guidelines for nutrition during pregnancy were published by the National Academy of Sciences. The Subcommittee on Weight Gain During Pregnancy revised the weight gain recommended for pregnancy. During the process of developing new recommendations, the subcommittee considered several factors that might help to determine the appropriate weight gain for an individual pregnant woman. Some of these factors include demographic and biological changes that might influence the effect of weight gain. Clinical issues that must be considered in implementing the weight gain recommendations include the importance of accurate weight and height measurement, categorizing the woman's weight for height, determining rate of gain at different times during pregnancy, and evaluating the significance of deviations from the expected weight gain pattern. A review of prior studies reveals that body composition changes, which might be important to consider in conjunction with weight changes, have not been well studied. Data are presented from a current study that indicates the problems encountered if traditional methods of body composition measurement are used during pregnancy.