c Significant difference (p < .05) between lactating and nonlactating subjects.
These measurements (like those for biochemical indicators) have been reported for very few women at any stage of lactation. Two longitudinal studies (Butte and Garza, 1986; Butte et al., 1984; Manning-Dalton and Allen, 1983) and one abstract (Heinig et al., 1990) provide the data base for examining anthropometric changes during lactation. These data reveal a consistent average rate of weight loss of 0.6 to 0.8 kg/month during the first 4 to 6 months post partum, although mean weight early in lactation differed among the groups of women studied (Figure 4-1). Heinig and colleagues (1990) followed lactating women longitudinally for 12 months and found that, on average, weight loss continued between 6 and 12 months post partum, but at a slower rate than that in the first 6 months.
Not all the lactating women studied lost weight post partum; for example,