Developmental milestones (newborn and infant): Clinical sciences

Developmental milestones during the first years of life are crucial for lifelong development and learning. These milestones are functional skills that follow a predictable sequence by specific ages, and are divided into five major categories: gross motor development, which relates to the movement of large muscles; fine motor development, which relates to the movement of small muscles; cognitive development, which covers reasoning, memory, and problem-solving; social-emotional development, which describes attachment to and interactions with others; and finally, language development, which covers both receptive and expressive communication.

Understanding normal developmental milestones will help you recognize when a child could be at risk for a developmental delay. Early intervention services can then be implemented to improve developmental outcomes.

When an infant presents for assessment of their developmental milestones, you should begin your examination with a focused history and physical exam. During the history portion, be sure to review birth history, including gestational age and birth weight; and remember to ask about family history of developmental delays. You should also take an interval history by asking the family what new skills their baby has learned since the last clinic visit. Additionally, ask the caregiver if they have any concerns about their baby’s development; since they spend the most time with their baby, they are often the first to notice when something isn’t quite right.

Now, here’s a clinical pearl to keep in mind! If the caregiver has a concern about their baby’s development, that’s a red flag; so, during your assessment, pay special attention to the caregiver’s concern!

The examination is also an opportune time for you to see first-hand what the baby can do. During your exam, take some time to play with the baby. A playful and interactive exam is entertaining for the infant and gives you a snap-shot of the baby’s development.

Now, at each visit, your goal is to assess the infant’s developmental milestones according to their age, using a combination of direct observation and caregiver reports. Shortly after birth, you should assess their neurologic and motor development by checking reflexes that are present in the neonatal period. For example, you can check for the rooting reflex by stroking the side of the newborn’s mouth or cheek, and in response, they should turn their head towards your hand while opening their mouth. After they open their mouth, you can check for the suck reflex by placing a gloved finger in their mouth and touching the roof of their mouth. Normally, an infant should begin sucking.

Finally, don’t forget to assess the Moro reflex, also called the startle reflex. You can trigger the Moro reflex with sudden movements or loud sounds; or, you can hold the baby horizontally and make a dropping motion with your hands. In response, the baby should throw back their head, extend out their arms and legs, cry, and then pull their arms and legs back in.

In addition to assessing developmental milestones, you should assess for red flags that may signal the risk of a developmental delay. These include prematurity, low birth weight, and caregiver indifference, meaning a caregiver that is not responsive to their newborn.

Now, let’s move on to the developmental milestones you should see in a one-month-old! Gross motor milestones include being able to lift their chin during tummy time, or the time they spend on their tummies; turning their head to both sides when laying on their backs; and moving both of their arms and legs equally. Fine motor milestones include keeping their hands fisted and near their face.

Cognitive skills include looking at faces. As far as social-emotional development goes, they recognize their caregiver’s voices, and they cry when distressed. Lastly, important language milestones include startling to loud sounds and making throaty noises.

Red flags you should look for include poor movement or feeding due to low muscle tone; not responding to loud sounds or focusing on objects within a few inches from their face; and caregiver indifference.

Okay, moving on to a two-month-old. By this time, the infant’s gross motor development includes being able to lift their head and chest when on their tummies; although their head lags when they’re supported in a sitting position. Fine motor skills include unfisted hands nearly half of the time and the ability to hold their hands together at midline.

Cognitive skills include opening their mouth when they see a breast or bottle, recognizing their caregiver, and looking at toys that are presented to them. Social-emotional development includes a reciprocal smile, which is when the infant smiles in response to their caregiver’s smile; and important language skills include cooing, which consists of vowel sounds like “ooh” and “aah;” and making sounds in response to their caregivers.

Red flags you should look for include not lifting their head during tummy time; and not looking at faces or responding to voices.

Now, let’s switch gears and discuss milestones for a four-month-old. In this case, the gross motor milestones include propping themself up on their wrists during tummy time, holding their head up straight and steady when sitting with support; and rolling from prone to supine. Fine motor skills at this age include open, unfisted hands most of the time. The infant also enjoys reaching for objects and playing with a rattle.