Does your baby seem healthy? Does he have a good appetite and everything?
Emma was only 2.9 lbs at 6-7 months of age, and we thought she would probably level out at around 3.5 lbs. Well, she had a bit of a growth spurt and is now just over 4 lbs at 2 yrs old and the perfect weight for her size. They will surprise you
Sometimes they grow steadily over time and some have growth spurts later on.