01.04 Growth & Development – Infants

Hey guys! Welcome to your lesson on growth and development for infants. In this lesson we are going to cover expectations for growth, motor, language and psychosocial milestones to be on the lookout for. We will chat about how this will affect your patient interactions and highlight important topics for education.

Remember, everything we do in peds goes through the developmental filter and this lesson is where you learn what that looks like for babies!
So infancy is a pretty intense time of life. From birth to 1 year everything is growing and changing super quickly and it’s a lot for the baby and the parents to handle. Honestly, I have an 8 month old and as soon as I get used to one routine it changes completely. So, yeah, it’s a lot! Because it’s happening so quickly. we have to watch our infants really carefully to make sure we detect any problems early on!


Okay so the physical growth that happens in infancy is occurring more rapidly than it will at any other phase in life. Babies double their birth weight by 6 months and triple it by 12 months and this is why babies totally eat like it’s their job!

As you can imagine- there are a lot of things that can throw a baby off course and cause problems with this. When this happens it’s called failure to thrive or weight faltering. This is something we have to watch babies really closely for by weighing them periodically during their first year of life and plotting it on growth charts. The two most important times to keep an eye on this is just after birth when they are learning to feed and then also whenever parents start to add solid foods to the diet, often this is around 6 months.

Two other physical assessment findings that are really important and only come up during your assessment of infants are the fontanels. At birth a baby usually has 2 open fontanels. The posterior fontanel closes first - usually around 1-2 months. The anterior fontanel closes anywhere from 9-18 months. We assess these fontanels because can tell us a few things. If they are sunken the child is likely dehydrated and bulging fontanels are a sign of increased intracranial pressure.


Okay - so one of the most important things you will come to get a feel for when it comes to assessing infants is their tone. Most of the time you’ll hear a baby described as either having ‘good tone’ or ‘poor tone’. It’s kind of a difficult to describe, but basically a baby with hypotonia or poor tone doesn’t have the normal tension and stiffness that are always present in muscles - sometimes we use the word floppy to describe these babies.

If you haven’t seen or held a baby with poor tone, please take a look at the videos in the resource section titled Typical vs Atypical development. They are awesome and will show you exactly what to look for in terms of tone. Remember, development happens from the head down. So starting with head and neck control at 3 months and moving to trunk control all the way to walking.

There are also some important fine motor skills that occur in the first year of life - check out the outline for a list of those!


Language development really begins around 4 months when a baby begins to do more than cry. They start to babble, coo and have high pitched squeals. Their first words usually occur around their first birthday which is also around the time they are taking their first steps. So that’s easy to remember - walk and talk by 1.

They are also understanding more than you might expect. By age 1 they know what the word no means and can follow simple commands.


Okay so for psychosocial development infancy is all about having a lot of needs and trusting that they will be met. This means their primary relationship is with the caregiver that is feeding them most often. A major milestone we are looking for during this time is the social smile- this usually appears around 6-8 weeks and it’s really important because it tells us that 1) a baby is getting facetime with an adult and 2) they are responding to it. This is a great indicator that the baby is well cared for and that their cognitive development is on track!

Two other important cognitive milestones are object permanence and stranger anxiety. Both of these usually develop around 9 months. Object permanence simply means that when an toy or something is moved out of sight they know it still exists. Stranger anxiety is self-explanatory. Just know that assessments and nursing care can get a little more difficult around this time because of this development.


Four common problems that can occur during infancy are Failure to Thrive, Suffocation, Injury and Abusive Head Trauma and you can see they are all pretty serious. We’ve talked about early detection being so important but honestly, what we really want is to prevent them from happening in the first place by educating parents. You can see how they are related to all the milestones we’ve discussed. Take a look at the patient education section of the outline for specifics on how to educate and provide support around these topics!

Your priority nursing concepts for this content are human development, patient centered care and health promotion
Okay guys, that finishes up our chat on infants. Like I said a lot happens in that first year! So let’s highlight the key points. Really, the 3 things to remember are Trust, Tone and Weight! If you remember these 3 words as the most important for infant growth and development you’ll remember why infants are high risk and easily recall your education topics and red flags to be on the lookout for!

That’s it for our lesson on growth and development during infancy. Make sure you checkout all the resources attached to this lesson. Now, go out and be your best self today. Happy Nursing!