All babies have their own individual growth curve and they do not all grow at the same pace. While your baby's slow development may seem alarming, it may, in fact, be absolutely normal as developmental milestones for all babies may happen a little off the average timeline. Slow development especially happens in babies that are born prematurely. If you still have doubts it needs to be double sure, it is always recommended to seek professional help from your child's pediatrician.