Changes in body weight and adiposity during lactation.

Studies from different parts of the world reveal subtle changes in body composition that indicate that differences in maternal nutritional status modulate the mobilization of fat depots during lactation. In the first three postpartum months, weight loss is a norm regardless of socioeconomic background. However, in regards to adiposity, differences between mothers of rich and poor countries will depend on methods of body fat measurement and a differentiation between the nutritional status of poor and affluent women. Whole body estimates of adiposity showed great variability even within the same studies, whereas assessments based on skinfold measurements showed conflicting results. Lactating mothers in less developed countries loose subcutaneous fat when measured as a single or as a sum of several skinfold measurements. Triceps skinfold thickness appears to be sensitive to short-term changes in marginally nourished mothers. Mothers from affluent countries will show more variable results in changes in body fat. In these women triceps skinfold always increased but the sum of multiple skinfolds could either increase or decrease. In the second trimester of lactation, relative differences in body weight and body fat between mothers of different socioeconomic backgrounds were less noticeable. All mothers showed comparable range of loss in percent body weight and percent body fat. Thus the effects of lactation on adiposity occur mainly during the second trimester, but will occur in the first semester in circumstances of relative maternal malnutrition. Copyright (C) 1997 Elsevier Science Inc.