4 Month Milestones: What are the Developmental Milestones of My 4 Month Old Baby??

Know everything to look forward to when your baby turns 4 months old

Medically Reviewed by: Dr. Kedar Patnekar (MBBS, D.N.B, D.C.H, Specialist Pediatrician) Dubai, UAE.

Author: Khushboo Kirale
>> Post Created: October 24, 2020
>> Last Updated: December 24, 2024

Your baby is 4 months old already!

Hey, is that the same baby?? Your baby looks so different now that many people are going to ask this question, and even you might sometimes wonder how much your baby has changed. Don’t worry, you are not imagining things.

When your baby hits the 4 month milestones, there are so many changes happening in their body that your baby can change in appearance all of a sudden and leave you wondering whether somebody swapped your child.

Your baby’s weight might have doubled by now, and they will be sleeping longer stretches at night, giving you plenty of rest as well.

But Beware!!! The 4 month milestones can also come with the dreaded 4 month sleep regression that happens due to the sudden growth spurts. Don’t worry, we will help you through everything. You just enjoy this golden time in your baby’s development.

Your baby’s personality is also developing and will shine like a diamond. Just watch your baby gurgling, babbling, and cooing their way into every one’s heart.

What are developmental milestones?

A newborn baby is adjusting to the new surroundings that they have been pushed into suddenly. Therefore, they are very cranky and fussy. But by the time they are 4 months old, they seem to be getting used the environment and are now looking to grow and develop quickly so that they can enjoy everything around them.

Developmental milestones is the way you will be able to check your baby’s development easily. It will be anything that the baby has not done before or anything that has not happened to them before.

You can easily observe the 4 month milestones through the sleeping patterns, feeding patterns, their weight and height, communication skills, their personality, etc.

This month they will start getting curious about the world around them. They want to know what happens when they touch, squeeze, throw, rattle, etc. objects. They are turning their random movements into experiments through which they can understand the world.

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4 month milestones: baby weight and height/length

One of the important 4 month milestones is that by now your baby has doubled their birth weight. This is a very significant development in your baby’s growth. A 4 month old baby will weigh around 13 pounds or more, although this is just an average and can be different for different babies. If your baby was premature, then they might take a longer time to double their birth weight.

This average will also vary for baby girls and boys. 4 month old baby girls can weigh around 10 to 19 pounds and their height/length can be around 22 to 26.5 inches, whereas 4 month old baby boys can weigh around 11 to 20 pounds and their height/length can be around 23 to 27 inches.

If your baby may not fall into this average range, then you don’t need to fret over it. As long as your baby’s pediatrician is happy with your baby’s growth, you should be happy as well.

4 month milestones: the five senses

Visual

This is one of the important 4 month milestones to look out for. Your baby’s eyesight has improved significantly this month.
Their vision is still not 20/20, but somewhere close to 20/40 or 20/50.
Things that were out of focus last month are finally visible to your child, especially things in close range.
Before hitting the 4 month milestones, your baby had trouble distinguishing color contrast. Therefore, newborns preferred very bright colored or black & white objects.
4 month old babies can identify subtle contrasts, like distinguishing a blue shirt color from the blue buttons.
They can also see people across the room, but they do like looking at people at close range. That way they can look at you smiling at their adorable gestures.
Your 4 month old baby’s eyes can follow moving objects easily now.
They should be able to follow objects smoothly now. If you notice crossed eyes or other problems with their vision with your baby, be sure to consult your pediatrician.
Their eyesight and motor skill development has ensured better hand–eye coordination. They will be able to grab things and move things more easily.
Giving them toys that they can hold and play with will help them improve these skills further.
Your 4 month old baby is also learning about object permanence. They have understood things have not disappeared from their sight. You, their favorite blanket, toy, or stuffed animal, etc. are still permanent and still around them.
Another thing that they have started seeing and enjoying is their own image in the mirror.
You can see their fascination with themselves when you keep them in front of an unbreakable mirror.

Smell & Taste

When it comes to listing of 4 month milestones, sense of smell and taste is something that is getting developed pretty fast. By now your baby is picking up things, most of those things will end up in their mouth. Tasting is how they understand and explore the world around them.
Never leave any small things lying around as they can be choking hazard for your baby. Remember that anything which can fit inside the tube of a toilet paper roll is too small to be anywhere near your baby.
Although they have started learning to explore their environment with the help of touch now, your 4 month old baby has always been using their sense of smell to recognize and explore everything around them.

Touch

- Your 4 month old baby is enjoying their motor skills by touching everything that their tiny little hands can grasp. They will love touching new things and explore their surroundings. Keeping objects of different textures, shapes, materials, etc. in the play room will enable them to enjoy their surroundings to the fullest.

Hearing

A 4 month old baby’s hearing is also improving day-by-day. It is because of this increased hearing ability that babies can distinguish voices and tones. Because of better hearing, your 4 month old baby will be able to learn to mimic the sounds that they hear. This mimicking is also a stepping stone to future speech development.

4 month milestones: all other significant changes to look forward to

Your 4 month old baby is a little bundle of joy. They are enjoying chuckling, smiling, and laughing spontaneously.
They enjoy their playtime immensely and can even cry when the fun time stops.
This means they have started to express themselves by conveying that they are happy or sad.
They are able to copy different facial expressions like smiling and frowning.
Their mimicry does not stop there. They are copying sounds and may even try to join oohhss, aahhss, gaas, etc.
Your 4 month old baby can also express through their different cries that they are feeling hunger, pain, or are just tired.
Your baby is stronger now because of the exercise they get during tummy time. Their muscles are stronger now.
Those mini push-ups during tummy time enables your baby to support their head by themselves now. If your baby cannot do that yet, they soon will be able to, just have patience.
Your 4 month old baby can now hold things with one hand and will be able to pass objects from one hand to the other.
Your baby will turn into a panda bear and roll over from their tummy to the front, and may even roll over from their front to their tummy again.
Your 4 month old baby’s legs are also growing stronger. They are getting ready to eventually start crawling and then walking.
As 4 month old babies can hold their head up, some of them will also be able to sit with support this month onwards.
Another significant change in the 4 month milestone is that your baby has understood cause and effect. They will see people around them respond to things they do. They will observe people rushing in when they start crying. They will see when they drop something on the floor, you will go and pick it up. So our baby Newton has understood that every action they do will have some reaction from you.
Your 4 month old baby will also find their feet very fascinating. Their feet will turn into toys that they can play with anytime, and for some babies may find them quite tasty too.
Another very important 4 month milestone is that babies at this age will start changing their eye color, especially lighter colored eyes will go through many color changes till they reach a more permanent color at around the time when the baby is 6 months old.

When to be Concerned?

As new parents, it is very easy to go overboard in monitoring your baby’s growth and progress. This monitoring and tracking can bring unnecessary stress if you see your baby’s growth deviating from the average.

Your baby’s growth deviations may cause you to worry and conclude that there is something wrong with your baby. But just because your baby has not reached a few 4 month milestones, you think that there is reason to be concerned.

But there are a few things that you should discuss with your doctor to help them understand and monitor your baby’s progress.

Contact your pediatrician:

If your baby is not following moving objects with their eyes.
If your baby does not smile.
If your baby cannot hold their head steady.
If your baby does not make sounds.
If your baby is unable to bring objects to their mouth.
If your baby is unable to support their body on their legs when you hold them on a flat surface.
If your baby is still unable to focus their eyes on an object and appears crossed eyed.
If your baby has gained less than 50% of their birth weight.
If your baby is unable to sit at all, even with support.

4 month milestones—your 4 month old baby’s feeding pattern

Your 4 month old baby is going through a growth spurt, and this growth spurt is fueled by breast milk (which is still as important as ever) or formula.

If you are still breastfeeding, then your 4 month old baby is mostly feeding 5 to 6 times a day, which can be around 24 to 35 ounces of breast milk in total each day.

Similarly, if you are feeding your baby on formula, your 4 month old baby will feed around 5 times a day, which can be around 24 to 36 ounces of formula in a 6 to 8 ounces bottle each day.

Your 4 month old baby has started sleeping longer stretches at night; therefore, their frequency of feeding will reduce significantly during the night. However, some babies going through growth spurts may require more frequent feedings at night.

Recent research has indicated the right age to start your baby on solid food is only after they reach the 6 month mark.

But as we know that all babies are different, and they are ready for solid food at different times. Some babies are ready for solid food as early as 4 months of age, whereas some babies may not be ready even when they are 8 months old.

You will have to look for your 4 month old baby’s cues to understand if they are ready for solid food.

The American Academy of Pediatrics (AAP) suggests to look at the following signs to check if your baby is ready for solid food:

Your baby is able to hold their head up high and can sit on a high chair or feeding chair without toppling over.
Your baby appears interested in food that you or other people around them are eating. They will look like baby birds opening their mouth to be fed.
If they don’t like food given to them with a spoon, they might not be ready for solid food. But if they actively seek to be fed with a spoon, this may mean that they are ready for solid food.
If your baby has gained double their birth weight or are anywhere above 13 pounds, they might be ready for solid food.

If you decide to start your baby on solid food when they are 4 months old, then remember to only feed about a tablespoon of fruit, vegetable, or baby cereal 1 to 2 times a day. This feeding will be only for practice and not for nutrition.

4 month milestones—your 4 month old baby’s sleeping pattern

Your little one is finally sleeping for long stretches through the night, giving you the much needed rest to recuperate after a day being at war with dirty diapers. But this is also the month for the dreaded 4 month sleep regression.

This can feel very frustrating because you were finally at a position where your baby was following a routine and was sleeping through the night. The 4 month sleep regression can throw your set routine for a toss.

Sleep regressions can occur during different stages of your baby’s development, but the first one occurs when your baby is 4 months old. This is also one of the important 4 month milestones. You can say your baby is going through the 4 month sleep regression if they previously followed a predictable sleeping pattern and are now:

Frequently waking up at night.
Refusing to sleep at night and don’t want to take naps as well.
They are more cranky and irritable

Sleep regression is often the result of growth spurts that affect your baby’s developing body. This situation is completely temporary and the best way to get through the 4 month sleep regression is to stick to the routine even if your baby does not want to sleep. Have detailed out 18 simple tips to deal with 4 month sleep regression which are sure to help you out.

It can get a little tricky to continue the routine when your baby is going through sleep regression, but laying them down to sleep at their normal nap times will help reestablish the routine.

Overall, you need to make sure your baby covers 12 to15 hours of sleep per day, even during sleep regression.

4 month milestones—your 4 month old baby’s health

As your 4 month old baby continues growing and developing physically as well as behaviorally, every tiny change in them will make you wonder whether this is a symptom for something and whether it is normal. We are listing a few of the common health problems that 4 month old babies might face:

Cold

Many babies suffer from cold in the first few months after birth. Cold is also called the upper respiratory infection and is caused by a virus. It is very common (hence, the name common cold) and contagious. Your 4 month old baby can also have a runny nose with yellow or green discharge. Having colds is very normal in babies and will go away with some home remedies and lots of care. But if you baby’s cold lasts for more than 10 days, consult your pediatrician.

Vomiting

One of the best things to feed your baby is breast milk, and if your baby has a stomach bug, feeding breast milk is even better. If your baby is vomiting and you have been feeding them formula, consider switching to breast milk. Breast milk is more easily digestible during illness as compared to formula or other replacement drinks. You can also try shortening the nursing sessions and then see if the baby can keep the milk down. If the baby throws up everything they have eaten in 24 hours, then visit a doctor immediately.

Fever

If your baby has a fever higher than 101°F after 4 months, you should seek medical attention. Having a fever usually means that your baby is fighting some infection. Fever can be an indication of common cold, ear infections, or even pneumonia. So it is best that you consult a doctor if your baby has a fever.

Teething

4 month old babies don’t usually teeth, but as the age range for teething is quite wide, it is possible. It is more common for the baby to start teething when they are 6 months old or more. But there have been instances where even 4 month old babies have experienced teeth eruption. If your baby starts crying more than usual, drooling, refusing to nurse, and massaging their gums helps calm them, then your baby might be teething – understand signs of teething. Consult your doctor to be sure.

Thrush

If your 4 month old has thrush, you will notice white patches on the tongue that you are unable to clean or white patches on the inside of the cheeks. Thrush is a mild yeast infection which is common in babies and can be easily cleared up with some prescription medicine like Nystatin. Infants can develop thrush if they are breastfeeding or if you or your baby is on any antibiotics.

Bronchiolitis

It is a common viral infection and is highly contagious. Bronchiolitis affects the breathing tubes. Washing hands and maintaining hygiene during the colder months can help reduce the spread of the infection.

Diaper rash

Those pesky diaper rashes are unavoidable. At some point all babies get it. Diaper rash will clear up in a couple of days with the help of rash creams. Diaper rashes can be prevented by using diapers that are made from natural materials like cotton, changing the diaper frequently so that the wetness does on last long on your baby’s skin, making sure the baby gets enough time without a diaper to ensure air circulation, upgrading the diaper sizes when the baby grows, etc.

You can also apply diaper rash cream or even try some home remedies for diaper rashes – like coconut oil, corn starch, baking soda bath etc. Even when you are travelling you can try some of the home remedies to avoid diapers rashes from appearing. But if the rashes are not clearing up in a couple of days and appear bright red, it could also be a fungal infection, which can be cleared with the help of anti-fungal cream. Keep your doctor posted if the rashes are persistent.

Constipation

If your baby is constipated, their poop will almost be like hard balls and their belly will feel hard and rigid. Consult a doctor immediately to relieve the baby.

Diarrhea

If your 4 month old baby’s poop is more watery and runny, then they might be suffering from diarrhea. Consult your doctor immediately.

Heat rash

A hot and humid climate can affect your baby and heat rashes may appear on the arms, legs, neck, or the diaper area. There is no need to apply any special creams or ointments. Try using cool water to clean the skin and then dry completely. Dress the baby up in dry and cotton clothing and keep them out of heat. Heat rash will typically go away in a couple of days. Contact your pediatrician if the rashes are persistent.

Eczema

If the crooks of the elbow and knees show red, itchy, and scaly patches, then your baby probably has eczema. Your pediatrician will diagnose the condition and provide treatment options. Avoid strong scented baby soaps and other baby products. Ensure that the clothes your baby wears are washed with mild detergents and are not prickly. Bathing the baby not more than 3 times in a week is preferable.

Allergies

Your 4 month old may also have some allergies or sensitivity that haven’t been diagnosed yet. If your baby is excessively fussy, vomits after every feed, the poop is very watery, bloody stools, rashes on the body, etc., then these could be signs that your baby is allergic to something. Consult your doctor to find the allergen that is affecting your baby and the corresponding treatment plans.

4 month milestones—checklist and tips for your 4 month old baby

First and foremost, you should visit your baby’s doctor for their 4 month check-up.
During this visit your baby will receive the second dose of the same vaccines that they were given when they were 2 months old. They will be given injections of the polio, Hib, DTaP, and pneumococcal vaccines, whereas rotavirus vaccine will be given orally. This is one of the crucial events as we list down 4 month milestones.
The fourth month is great time to take your baby swimming. Babies can achieve the 4 month milestones faster in water than they can on land. Babies generally enjoy swimming and it also helps strengthening your baby’s muscles, especially legs.
Your 4 month old baby will also look for more entertainment and stimulation this month. Trying different activities can keep them entertained and happy.
Playing peek-a-boo is one of their favorite activities this month.
You can even hide a toy and cover it with a blanket and let them find it.
Introducing toys that your baby can hold and rattle or squeeze will help them exercise their arms and also enjoy at the same time. But remember, no matter the toy given, your baby will bring the toy to their mouth and taste it. Don’t worry, this is completely normal, they are just trying to explore the environment through taste.
Reading from colorful board books with different textures will help in stimulating you baby’s brain.
Reading and even singing (even if you are out of tune) help your 4 month old baby grasp words better, and they try and mimic them.
Continue giving your baby ample of tummy time. Scatter a few toys on the play mat and see them try and reach the toys. This will improve their muscle strength and hand–eye coordination.
Help your baby sit in your lap, or a chair/sofa with support. You can also keep your breastfeeding pillow behind them for better support when they sit. This will enable them to sit independently in no time.
Even if you feel your baby is able to sit properly, never leave them in a sitting position unsupervised. When you 4 month old baby is just learning to sit, they tend to topple over. Without supervision, this toppling over can hurt your baby. So stay alert.
Along with sitting, you should also make your 4 month old baby stand. Hold them and let their feet touch the flat ground. This is a good baby workout for leg muscles.
Even though your baby cannot crawl or walk yet, they might just be rolling over like a pandas. Ensuring that you baby proof the house right now can help avoid any mishaps that you can encounter in the future.
Last but not the least, don’t forget the baby photos. If your baby has started sitting, then this is a very good time to schedule a baby photo shoot. As they are not mobile yet, they are less likely to ruin the shoot.

Final thoughts

Many parents fret over the 4 month milestones. If your baby does not have a check in front of each milestone, you get a reason to worry.

These milestone are not power boosters that your child needs to collect before they can level-up like that in a video game.

Many parents are also under the misconception that all the milestones need to be sequential. This is far from the case. Your baby will hit certain 4 month milestones early and certain other 4 month milestones late. This is completely acceptable.

Just enjoy this time with your little bundle of joy rather than worrying about the 4 month milestones. Your doctor will inform you if they have any concerns regarding your baby’s development.

Khushboo Kirale

Hi, I am Khushboo Kirale-Thakker, a marketing specialist turned homemaker and mom of four (1 elder daughter and triplets—all boys). Me and my husband started this blog to help other parents like you with some first-hand experiences and insights on managing twins, triplets and kids in general. My journey has included experimenting with different baby products from around the world, transitioning from a high-flying job to a full-time mom, tackling pregnancy complications, trying home remedies, etc. Feel free to connect with me through this blog on any queries you have.