how to gain weight for newborn baby who is 20 days old

A. Hello good morning !! As baby is new born weight may loose in initial two weeks but later on they gain around 400-800gm per month. By 5-6 months they double their birth weight... check if baby increasing ideally every month,yet there is time don't worry. Give feed every two hours, exclusive breast milk or formula milk until 5 complete months and sleep around 14-18 hours a day, sleep is also important as sleep impacts growth harmone...