Is it normal for 5yo to lose a pound ? she was 40 in june now 39.1

COMMON: While length increases without any losses,a kids weight will vary day to day.Sometimes due to obvious issues like an illness,emotional stress or because they go through a growth spurt and use it for length. One of the more common reason for an apparent difference in weight is use of a different scale. When I see this I just monitor it over time. If it seems to be a trend, I look into it.