Your Baby’s Development. 4-month-old Milestones and Signs of Delay.

Last Updated on 17 March 2022 by Dott. Sandro Cantoni

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At every age your infant and toddler plays, learns, talks, and moves. Seeing when and how it does these things is critical. Because from this you can know if the baby’s development is normal or not.

This observation of developmental milestones can be done by any parent just fine. It’s not a matter of doing special investigations or tests, but just watching some simple daily activities. 

In fact, I believe that parents are the best people to evaluate the baby’s development. Because they know him perfectly in all its facets. The parent is able to pick up on nuances of behavior that the pediatrician often fails to detect. 

What are the developmental milestones?

The developmental milestones are the things that most babies do at a certain age.

Don’t worry if your baby doesn’t reach all the typical developmental milestones for his or her age right away. 

Every baby is different. Some babies develop faster, others a little slower. But this is often normal. 

Some babies walk at 10 months, others at 18 months. 

The achievement of developmental milestones also depends on gestational age. If the baby was born one or two months premature, then he or she will reach the milestones one or two months later. 

If you think your infant or toddler’s development is not normal, ask your pediatrician for a checkup. 

Don’t wait until the next checkup in a few months. If your baby does not reach the developmental milestones typical for his or her age, call the pediatrician. Do the same if you have concerns about how your baby is talking, playing, acting or moving, or any other concerns.

Don’t wait. Make your doubts and concerns clear to the pediatrician.  

In the event that there are problems, early detection and early intervention, as soon as possible, are critical. 

What are the developmental milestones for a 4-month-old baby?


If he is placed on his back, the child will move more and more, symmetrically.

By now he often holds his hands open and moves them well. Then the child looks at his hands, puts them in his mouth, seems to play with his fingers.

He can use his eyes and hands, for example he looks at a toy and tries to reach it with one hand. 

He begins to pick up objects, even if he lacks some coordination, he looks at them and brings them to his mouth. If he has a rattle he starts to shake it. He also grabs clothes, your hair, and anything else that comes within reach, and brings it to his mouth. 

He can’t use his thumb to grab toys. He picks them up with his fingers and palm.

When lying on his belly, your baby lifts his head and chest well, resting on his forearms. Then, still in this position, he turns his head in all directions to follow an object or person.  When your child is placed in a sitting position, he keeps his head stable. 

If he is placed standing on a hard surface, he puts his feet on the floor and tries to support himself and bear his weight for a few seconds. He turns well on his side, although often unintentionally, . 

He may begin to roll over, especially when lying on his stomach. In this position you can often see that the child stretches out one arm and then rolls onto his back, so involuntarily. Then he understands how to do it. 

Since his ability to move has also improved, he tries to reach for a toy that interests him with body movements.

For example, he shakes his legs, or tries to stretch, or roll over, if he sees an interesting toy.

Vision, hearing

The vision improves and the child loves to look at his environment. Especially the parents’ faces. He looks at you often, for a longer time. If you show him a toy and move it to the right or left, the child follows it with his eyes. He recognizes you even if you are far away. 

The child listens carefully to sounds or music or your voice, and turns toward the source of a sound. He is attentive if you call to him and he turns around.  

Communication and language

At this age, her language range has clearly increased. The child makes vowels all the time, and plays at changing the intensity and pitch of various sounds.

He smiles at you more and more when you play with him. He tries to communicate with you, or get your attention, with sounds and vocalizations. He also often laughs to himself. He begins to introduce, in his vocalizations, some features of the native language.

He clearly shows pleasure in playing with you, and often cries when you have to go away. The child shows that he is happy when communicating with you . 

He is more expressive with his face and body. He reacts to everyday situations with smiles, vocalizations and movements of excitement before some pleasant moments such as feeding or bathing. Manifests pleasure during moments of cuddling and massage.

Affective and intellectual development

The child is often happy and smiles. He makes it clear that he is happy when he sees his parents, clapping his hands, or reaching out to be picked up.

He likes to be massaged and stroked. He bursts out laughing when you play hide and seek or at other occasions, as if imitating his vocalizations. If you ignore him for some time, he often cries or fusses for attention.

The child is easily calmed and comforted if you pick him up. When a stranger approaches him, he is often diffident. For example, he stops smiling and becomes agitated.

The child often observes his environment and what is going on around him.  He does not yet have the concept of object permanence. That is, he looks at a toy, but if you put it out of his sight, he looks away and does not search for it.

What are the warning signs for possible developmental delay at 4 months?

  • The symptoms that should alert you are these:
  • The child does not move harmoniously and symmetrically. But jerky or asymmetrically, that is, for example, moves one arm better than the other. When laid on his back, he does not lift his head.
  • Also, when laid on his stomach, he does not keep his head raised to 90 degrees. He does not try to lift himself by holding on to his forearms.
  • If you put him in a sitting position, the child cannot control his head, but it tends to fall down or sideways. 
  • When you hold him suspended on his stomach, he cannot keep his head on the horizontal line.
  • When held upright, he does not push with his feet toward the surface.
  • The child does not try to grasp objects. He does not show any interest in the toys you put in front of him. And he does not try to pick them up to touch them when he is sitting, or when he is lying on his back. He does not bring objects or hands to his mouth.
  • The child does not look at the parent’s face, or follow his gaze. He does not seem interested in looking at you. Then he does not look at objects when they move and do not move both eyes in all directions. He often crosses his eyes, as if he were squinting.
  • Also, the child does not smile. Does not produce sounds or vocalizations. He does not calm down.

If your baby has any of these symptoms or if you are worried, talk to your pediatrician. Don’t wait. Early detection of a possible problem is crucial. Early treatment is critical.

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