4 month milestones

Your baby’s 4 month milestones especially focus on sociability: your child will want your company all the time and will be showing more and more affection.

You’ve been going full steam ahead since your baby came into your life, and time is flying! You keep crossing off days on your 'mum's calendar', as your little one makes progress rapidly. He's already four months old, without any doubt a phase that will mark a before and after in his development. Among the 4 month milestones, sociability stands out as the most remarkable characteristic that your newborn will be developing. He wants you to keep him company for as long as possible, and you can see that desire reflected in his cute face. He smiles, laughs and gurgles at you to express his joy when you are around, whereas you can expect him to cry a lot whenever he feels lonely. The baby still wants to feel cuddled and snuggled!

Check out some of the usual 4 month old milestones and learn how to take maximum advantage of this enchanting period, for both you and your child.


4 month milestones: Slowing down

By now, your baby should be twice as big as he was at birth. He's been growing up fast, but this steady rhythm will change in the second trimester of his life. The 4 month old baby's development is slower in terms of height and weight. He'll put on around 140 grammes a week, reaching 6,1 kg of weight gain, on average, by the end of the month. Also, he's expected to measure around 63 cm. But remember that the average numbers are just a reference and, if the baby doesn't fit squarely into them, don’t worry; every human being is different.


4 month milestones: It's not about me, it's about us!

As it's been already pointed out, one of the most remarkable 4 month milestones is the baby’s expanding social skills. His understanding of his surroundings is getting wider and he can now distinguish between himself and everything else he sees. That's why reaching out to objects and people will become his new favourite 'sport'!

But there are a lot more things that your baby can do now. Here are some things you can expect to see:

  • Following objects and people with his eyes becomes a faster and a more natural action
  • Staring not only at your eyes, but your whole silhouette
  • Incorporating colours into his visual perception (if this hadn’t happened previously)
  • Recognising familiar objects and people from far away
  • Improving eye-hand coordination
  • Strengthening his movements, especially at an arm/leg level
  • Becoming more dexterous with his hands, which he now uses to reach out and grab for anything. Be careful with your hair, as he may want to touch it and could accidentally pull it out. (He doesn’t know his own strength yet!)
  • Drooling increases, the first symptom of the next step: teething
  • Controlling his head and keeping it steady while sitting
  • Babbling and speaking syllables like 'ma' or 'pa'
  • Behaving differently in front of people he doesn't know

As your baby becomes more energetic and curious, make sure to keep his surroundings free of harmful objects. Don't forget that he'll try to pick up anything, above all colourful and shiny stuff. Not only could he get hurt, but he could also choke on them if he puts them in his mouth (another common routine at this age).


4 month milestones: Keeping his appetite under control

As we've already mentioned throughout this special set of articles dedicated to baby milestones month by month, your four-month-old will exclusively feed on milk, either by breastfeeding or baby formula. So far, that's all he needs to keep his nutrition level at its best. If you provide him with formula, he can drink up to four bottles a day. Paediatricians advise against introducing any complementary food yet.


4 month milestones: Nighttime, finally a comfort zone

The baby is not only learning how to manage his body and conceive the new world that he's been brought into; he is also adapting to it at a high speed. Sleeping still occupies a considerable amount of time, but his internal clock is finally following the 'day-night' routine. The baby's sleep pattern ranges now from 15 up to 18 hours every day, including naps (three or four throughout the day) and nighttime. The latter will become a 'comfort zone' for the baby, who can sleep between 8 and 10 hours in a row. Yet it is important that you create a bedtime atmosphere that involves snuggles, music, bathing and food, so he can be more relaxed and ready to have sweet dreams.


4 month milestones: Doctors & Vaccines

Your 4-month-old will need another necessary checkup by the doctor, who will test his physical development taking a look at his head, eyes, mouth, body (including muscle reaction), belly, hips, legs and genitals; and, also, listening to his heart and lungs with a stethoscope. The examination performed by the health visitor will also cover the weight and measurement of your baby. 

During the checkup, the doctor will ask you questions about how the baby eats, sleeps and acts under many circumstances. This information allows him to figure out if any problems may or may not be occurring in the baby's development.

For a kid this age, the vaccination calendar involves:

  • A third dose of the 5-in-1, which protects the baby against five different diseases, such as diphtheria, tetanus, polio and Haemophilus influenzae type b, and whooping cough.
  • A second dose of the Pneumococcal (PCV) vaccine, which prevents infections like pneumonia, septicaemia and meningitis. 

Finally, don't forget to bring a list of questions for the doctor. Don’t go home or let the doctor leave without having asked all of your questions and expressed all of your concerns.


As you can see every day, you are participating in a very special moment for your son or daughter. The 4 month milestones are another part of this incredible process of growing into an adult. He is shaping his body and communication skills while becoming more aware of his surroundings, where you, as his mummy, occupy the most important spot.