my baby birth weight is 3.4 now she is 3.5 Month old.. her weight is 5 kg.. and she looks very lean what can i do.. im breast feeding only

A. hello of the baby is gaining w minimum of 600 grams to 800 grams per month then it is a good weight gain and it is an indication that the baby is getting sufficient breast milk and is not a problem.. and 8f the bm is not sufficient then you can be giving your child infantn formula