how do you measure a underweight baby?

Answer 1

Go to cdc.gov and look for growth charts. You weight your baby and measure their height and then look on the chart to see where the baby falls. An average size baby would be in the 50% percentile. A child should stay in the same percentile, so if he is in the 10% that is ok as long as they don't go from the 70% to the 10%. If the child isn't on the chart then take them to the doctor. The doctor should be plotting their growth on one of these charts anyway at all of their well visits.

Answer 2

Here in the UK we are given charts/graphs which show the average weight of a baby at each week/month old. Some babies are born smaller or bigger than others though, so are not going to fall on the average line. I think the general rule is that as long as the baby continues to put on and not lose weight, and are in proportion for height/length, there is not too much to worry about. But see your health visitor/midwife/doctor/baby clinic if you are worried.

Answer 3

just like any other baby. put it on a scale, then ley it down on its back and measure from head to toe. you wont know if its underweight or not until you measure it.