Your Baby’s Development at 4 Months

Around 4 months, your baby is showing increasing awareness and interest in the environment! Advancement in his/her head control, visual skills, and fine motor skills allow the 4-month-old to demonstrate more and more purposeful movement. With these more refined motor skills, he/she is able to actively reach with increasing accuracy and begin to explore toys and his/her own body.

Supine (While laying on their back)

While in supine, the 4-month old baby is able to maintain his/her head in the middle and tuck their chin. This allows your baby to visually examine his/her body, including the hands, trunk, and eventually the feet, allow him/her to begin to build body awareness. He/she cannot yet lift the head up off the surface, but can easily rotate his/her head side to side when watching a moving object or in response to sounds. Your baby at 4 months can flex his/her hips and knees to align them with the body, indicating increasing abdominal strength. Your baby may also be beginning to roll from his/her back to the side. Babies at 4 months present with symmetrical arm movements, meaning they will often reach for both hands when reaching for an object, however may reach the object with one hand before the other. They are able to bring their hands to the middle of their body and enjoy exploring their body (face, chest, hips, flexed knees), continuing the development of that body awareness. Exploration of clothing also provides different tactile opportunities for baby’s hands. Your baby may be showing improved accuracy when reaching for toys, especially those close to the chest, but may miss targets that are farther away. He/she is also unable to voluntarily let go of an object, however may drop toys when no longer attending to them. At 4 months, your baby can track an object horizontally with ease and is showing improved downward gaze, allowing them to explore his/her body, hands, and toys.

Prone (Tummy Time)

During tummy time, your 4-month-old can lift his/her head to 90 degrees with increased activation through the abdominals. He/she is able to prop on elbows, lift his/her chest from the surface, and may be beginning to push up through extended arms. He/she cannot yet reach while on his/her tummy. Your baby may accidentally roll from belly to his/her side or back, usually coupled with a look of surprise! He/she may also demonstrate the pivot prone position, also known as “swimming” or “flying”; in this position, your baby extends this/her arms and legs, rocks back and forth, and then returns to a forearm propping position; this demonstrates the 4-month-old’s early coordination of the muscles on the front and back sides of the body!

 Sitting

Your 4-month-old baby may be able to sit unsupported for a few seconds. He/she likely enjoys being in the supported sitting position as it presents a new viewpoint from which to explore, however cannot yet reach for toys in this position. When pulled to sit from a supine position, the 4-month-old is able to demonstrate a head tuck and activate the abdominal and arm muscles to assist, no longer demonstrating a head lag.