My baby had his 6m appt today (born Sept 1 - 5lbs6oz) and he is now 16lbs 7oz and his doctor said expect for his weight to start slowing down.
Babies definitely stop gaining as much at this point, my LO did the same in the last 2 weeks or so she stopped gaining, I go to a breastfeeding support group and the LC told me to give her an extra feeding and last group she gained 2oz.
They start to slow down at that point my son is 6 months and he still eats quite frequently but isn’t gaining as much anymore, it’s just their bodies fluctuating and actually metabolizing and since they are more active it reduces the weight gain