4-Month-Old Baby: Development, Milestones, Feeding & Sleep

In the fourth month, your baby is growing and developing no less fast and intensively than during the previous three ones. The 4-month-old baby – is a social creature!

Physical Development

The rapid development of all organs and systems of organs of the baby doesn’t slow down. The 4-month-old baby will gain approximately 1.8 pounds of body weight, his height will increase by about 1.2 inches.

You can tell that the respiratory system of the baby is also improving by the following showings. The four-month-old baby’s volume of breath per minute is two times as much as such of a newborn baby.

The anatomic and functional progress of the digestive system also doesn’t remain behind. The area of the stomach mucous membrane surface has grown three times by the fourth month.

The central nervous system amazes with its rate of cellular and tissue development at this stage, which directly affects the peculiarities of psychical development (we will speak about them a bit later). The nature of the baby’s nourishment has a great influence on the development of different analytical and regulative brain centers’ cells, which now are quickly forming mutual connections.

The great importance of breastfeeding for the successful development of the little human being’s nerve centers should definitely be noted. A number of the components of a mother’s breast milk (amino acid taurine or long-chain rich omega class acids) are extremely important for the intensively developing brain of the baby.

Main Indicators

Height – 23.7-24.1 inches – Weight – 13.5-13.9 pounds

Head circumference – 15.7-16.1 inches – Chest girth – 15-15.4 inches


Many pediatricians are convinced that the 4-month-old baby needs exclusively breast milk for the complete provision necessary for productive growth and development chemicals. In other words, the 4-month-old baby definitely doesn’t need any vegetables, fruit, or other supplements. The only thing you may add to breast milk, pediatricians say, is vitamin D, which prevents the baby from having rachitis. That’s why the additional introduction of vitamin D as a daily supplement to the little one’s menu is recommended by doctors. Summarizing the things mentioned above, we recommend you not to hurry, changing the diet – breastfeeding is the best option at this time.


Main Activities

At this stage the baby begins to play with his own hands, the movements of his arms become free and purposeful – he brings different objects to his face (or the mouth), reaches for his toys, plays with the rattle, claps his hands, and drags them into his mouth. Lying on his stomach, the baby can rise, leaning on his elbows and forearms, he is trying to sit if someone supports his butt.

The baby is turning from his back to the side, is attempting to hold his head upright. In the fourth month, it will be good for a baby to hang up a mobile above the crib. The little one will be enjoying himself while playing with whirling objects and listening to music. Consequently, the interdependence between vision and hearing is being formed.

Learning New Skills

Now it is recommended to form the connection between looking down and sitting down in the baby’s brain. Though the baby will be sitting down only by the age of six months, you may pull him up gently by the arms already at the age of four months.

If the baby won’t learn to look at his own feet, the correct coordination of movements in the sitting position will take a longer time in the future. During the pull-up, the head of the baby should be drawn to his chest and the tension in the arms’ muscles should appear. Many pediatricians admit that an important stage of psychophysical development in the fourth month of life is the formation of body reactions and the vertical axis of the body.

The above-mentioned skills are necessary for the little human being’s “self-consciousness”. The baby that is able to rise from the surface feels the limits of its own body and starts to understand that a table or a bed are not its extensions. That’s why the babies that have difficulties turning around are later experiencing complications in forming self-concept. At this stage of the development of the baby, the first attempts of revaluation of space notions are happening. The things that were behind are now below; what was on the right is now on the left.

We will consider turning the baby’s head to the side as the very first attempt. You can watch the counteraction of the baby’s body muscles. The head is turned to one side, and the tension in the body muscles should appear on the opposite side. Neither the arms, nor the legs of the baby are deliberately chosen as support so far, but their interaction becomes the basis for turning from the back to the stomach and backward. This significant event happens, as a rule, at the age of three or four months.

At this stage, the baby can be awake for one or one and a half an hour in succession.

You Should Frequently Visit Pediatrician

Firstly, because at this age the little human being has to undergo serious vaccination – a complex of inoculations. Secondly, the possibility of allergy, rachitis, or colic hasn’t been excluded yet. If the baby makes it clear that he’s suffering from any ailment you should immediately consult a specialist.

Four-Month-Old Baby: Psychical Development

How are you supposed to understand why the baby is crying? What actions should be taken by the parents for the little one to calm down? Nature and distinctive characteristics of the crying itself will help you in this matter. You only should listen to it attentively.

  • The cry of hunger is usually louder than any other one. It often starts with minor sobs and then suddenly picks up intensity, becoming piercing. Such crying indicates that the baby is ready to be fed.
  • The cry of sleepiness is, as a rule, accompanied by rubbing the eyes, drawing the head back. The parents should help the baby to fall asleep by lulling him and keeping silent.
  • The cry of pain begins suddenly, often rising very high immediately. At this age the, babies most often experience pain in their stomach or ears.
  • If the baby’s intracranial tension is increased, then, as a rule, he is crying at the same time and at the same rate every evening.

The Easiest Way to Calm a Crying Baby Down

Sometimes you may unswaddle the baby and let him suck the own finger. These alternative means have their advantages – the finger won’t fall down on the floor, it won’t need boiling, and you will be able to easily find the baby’s hand even in complete darkness.


Hearing and Vision of the 4-Month-Old Baby

In the fourth month of life, the baby can fix its gaze and watch a bright object for five or six minutes. The little one could concentrate on the objects before only if he was lying on his back, but now he can do it when the parents hold the baby upright in their arms. The little human being can pick up the direction of the sound and turn his head to the source of it. Now the baby isn’t looking for the breast but opens his mouth immediately when he sees it coming.

The little one recognizes his mother, smiles readily at his parents and familiar people. The baby laughs if he is content and cries if he feels any discomfort. The child’s babbling is increasing and occurs more often. With each new week of life the vocal demonstrations of the baby become more and more varied – the pronounced vowels, as well as consonants, are often merged together, forming the simplest combinations like “aaaaheeeeeh” or “gush”.

Such vocal demonstrations are evidence of considerable progress in the development of the emotional sphere of the baby. At this age, the babies are babbling when they are in a really good mood.

The Baby Loves Music

Now it’s best to tickle the baby’s ears with calm tuneful compositions. Classical academic music will be an excellent choice. The baby’s mimic movements are becoming more and more expressive and informative for the mother and father.

Now your baby desperately needs constant attentive care of his parents and continuous gentle attitude as much as during the previous months. The baby likes it very much when his mother or father takes him in their arms, talks to him, tells him about everything that’s happening around, reads to him aloud, or spoils him with endearments.

In the fourth month of life the baby concentrates his gaze on the face of an adult person talking to him while someone is holding the baby upright in their arms, it listens attentively to the voices, answers the conversation with a smile, animated movements of the arms and legs, babbling. Such manifestations of joy during the conversation, which are natural at this age, are called “animation complex”.

Your baby is an almost full-fledged companion. The baby’s sense of smell is developing, along with the recognition of faces and voices of his mom and dad the little one can “smell out” his parents. Such recognition of loved ones can be accompanied by a smile, babbling, and general liveliness.

By the 12th-13th week, the baby will learn to fix his gaze on an object, which is being moved in an arc in front of his face at a distance of 6 inches from him and over the range of 180° from one side to the other. The baby will also be able to concentrate on a very small object.

The showings and achievements described above shouldn’t be interpreted as absolute standards. Don’t worry or panic if your child doesn’t meet these descriptions in some way. In rare cases, the delay can indicate the existence of some problems, but most often it doesn’t add up too much, and your baby will be perfectly fine.

Everything Depends on a Person

For example, prematurely born children are usually reaching these main indicators later than their peers, closer to their biological age, in other words, at the age they would have reached if they had been born on the term. The mother has enough troubles and problems at this stage of the baby’s development.

She is likely not to have enough sleep and to get absolutely exhausted. So, there is no reason for unwarranted worry and panic. Keep an emotionally positive atmosphere around your baby. Let him have his swing, and your baby will surprise you with his talents more than once in the future.

4-Month-Old Baby Pictures

Check out how a 4-month-old baby looks like.