my daughter was born 2.5kg. after 1 month and 15 days her weight was 3.2 kg. then after 1 month it was 4.1 kg. again after 1 month it was 5.2 kg. now she is 5 months old and her weight is 5.8 kg. previous month's her weight gain was approximately 800gm-1kg. but last one month it was only 500 grams. she is taking breastmilk as usual. but her weight gain this month is less than the previous months. is it ok? any cause of concern?