My baby is 5 months old & she is not gaining weight since one month. Giving breastfeeding & 1 time formula milk at night. Multivitamin & iron drops are given by doctor. Please advise how to gain weight.

A. make sure the child is getting enough milk and it is taking well and also if the breast milk is not sufficient you can increase the frequency of infant formula milk which should be a better option so baby gaining a minimum of 600 grams to 800 grams is a good weight and nothing to worry