my son weight 3.8kg for 75 days, is this normal? birth weight is 2.75 , just intake mother milks only ? how to improve his weight

A. No Ma’am this is little less your child should be 250 g more than the current weight because the child is expected to gain 500 g in a month if your child is 75 days and the child is approximately 250 g less than the expected weight gain