Nishitha please do not worry about the weight part if the baby is active and achieving milestone, 6.09 is not underweight.

Hi nishita 
Baby weight should be double of his birth weight while he reached to 6 month 
<a href="http://app.babychakra.com/article/2623">Understanding Baby Weight Gain</a> this article will help u

Hi fndz today my baby is 3.5 months now and he is 6.090 kg is his wt all right or he is underweight??? He is very active always playfull.