Why has my month old baby lost weight?

Q: My baby is a month old. Three days back, his weight was 3.65 kg and now its only 3.42 kg. How could this happen? I have been feeding him properly. Does spitting up cause weight loss?

A:It is possible that the first weight recorded was inaccurate. If the weight was recorded on a spring balance then it is extremely difficult to ensure accuracy and reproducibility. Please ensure that the weight is recorded on an electronic digital scale, without clothes or diaper and then assess weight gain. It is unlikely that your baby has suddenly lost weight.