my baby has lost 800 GM's of weight in 19 days what will be reason and is there anything to worry about it

A. In Initial 30 days of birth a child can lose about 200 to 500 g of weight due to jaundice or something but if your child is losing more weight over that also then it would be maybe more of jaundice or maybe your child is not taking proper feed which is why the wait is going down so just discuss it with your doctor so that you can have a better understanding and a clarity over this issue