My baby is not gaining weight according to his age he is between 5-6 kg but he has started crawling. He is completely under breastfeeding, I haven't started formula milk. Can you suggest how can I increase his weight?

A. accordingly baby shpuld be double the birth wt at 4 to 6 months and three times the birth wt at one yr .. it is exclusively breast feed recommended for 6 months.. start with multi vitamin supplements as zincovit drops