4 Month Old Baby Milestones And Development – New Parents Guide


Your 4 month old is more alert, engaging, and loves to express himself through smiles, laughs, coos, and gurgles. His muscles are firmer and stronger now, so no more wobbly head. His senses and mobility have improved greatly too, and his tummy is big enough to let him sleep through the night.

Cherish this moment but don’t get too used to it. Your little person is growing up!

Stick with us to find out what to look forward to as your baby hits the exciting 4 month old milestones.

What You Should Know

  • Talk to your pediatrician about starting baby on solid foods this month
  • Take your baby to his 4 month old checkup and schedule his 5 month checkup
  • Baby is likely putting everything in his tiny mouth. Examine the floor regularly for small objects that could chock the baby.
  • The baby may be showing early signs of his first teeth
  • Spend a few minutes singing or reading to your child every day. He will love being close to you and listening to your voice.
  • Though baby may not have started rolling over yet, this is a good time to think about baby proofing your furniture and living room. Snap gates across stairways, put locks on cabinets, and store potentially dangerous products from baby’s reach. 

The Most Adorable 4 Month Old Milestones

You have hit the 4 month mark and the busyness and fussiness of the newborn stage are nearly over. Life is a little less hectic now, as you have established daily routines that work for you and baby. Congratulate yourself, mama, because you have done your job to perfection! Consider planning a photoshoot for your little one to capture all those adorable moments of your 4 month old baby activity. Here are some of the changes and developments you may want to document.

1. Weight And Length

At 4 months, the baby will have hit a huge milestone in terms of weight. Most babies will weigh almost double what they weighed at birth. On average, a 4 month old baby will weigh about 15.3 pounds for boys and 14.1 pounds for girls. The average height would be around 25.3 inches for boys and 24.2 inches for girls. 

Of course, not all babies will have this exact weight and length because babies hit milestones differently. Also, these parameters may be impacted by many factors; your baby may weigh more or less your friends’ 4 month olds and still be healthy. If he has been showing a steady and healthy growth curve, then there should be nothing to worry about. 

2. The Senses 

Your baby is more alert because his senses have greatly improved.


During the newborn stage, the baby could not distinguish color contrasts and that is why he preferred black and white objects or bright colors. At 4 months, the baby’s vision has become more enhanced and sharper and he can tell the difference between different shades. He can now see as far as across the room, but he still prefers looking at much closer objects. 

This can be a good time to familiarize the baby with toys for 4 month olds, more colorful objects, and books you think he will love to look at. 

You may also notice that the baby’s eyes move smoothly together now and he follows people and objects around the room. If the baby’s eyes are crossing at this age or if he is experiencing any other sight issues, talk to your pediatrician. 


Baby can recognize your voice when you speak. He listens when you talk and even tries to imitate you. 


Anything with texture fascinates baby now, and most of the objects he touches, no matter the texture (shiny, crinkly, furry, or lumpy) will go directly into his mouth. Be on the watch because babies will sometimes hit themselves in the face with the objects and start to cry!

3. Motor Skills

What should a 4 month old be doing, you may ask? 

At 4 months, your baby will become more dexterous and do more with his hands. He will grab and shake a toy with both of his hands. And as we just mentioned, anything your baby touches with his little hands will likely end up in his mouth, as tasting is how he explores his world. Here is more of what your baby will be doing as he achieves the 4 month old milestones. 

  • Roll over from his tummy to his back
  • Teething may already have begun so you will likely find drool on anything he lays his hands-on
  • Sit upright if supported
  • Hold and let go of objects. Baby is more attracted to shiny and colorful objects, so you may want to remove any necklaces or earrings if you are not ready to deal with a painful tug.
  • Kick and push with his feet
  • Push elbows up when lying on his stomach
  • Bear his body weight when standing on a flat surface
  • Smile and laugh spontaneously
  • Become more social. He loves to play with other people and may even cry or get fussy when playing stops.
  • Copy movements and facial expressions. The baby may try to smile when you smile and frown when you frown.
  • Cry in different ways to communicate different things like pain, hunger, or being tired
  • Follow moving objects with his eyes from one side to another

4 Month Old Food

Many first-time parents ask, “How much should a 4 month old eat?”

A 4 month old should eat about 6 to 7 ounces every 5 or 6 hours if he is on baby formula. Exclusively breastfed babies should nurse about 7 to 8 times in a day (24 hours). 

At 4 months, the baby is sleeping longer, which means the frequency at which he needs to feed is reduced. However, there are instances when your baby may still need to feed more often such as when he is sick or when he is experiencing a growth spurt. Learn how to tell baby is hungry so you can know when to feed him.  

At this age, you could also be wondering if it is the best time to start solid foods. Back in the days, doctors used to say it is okay to introduce cereal to infants at 4 months. However, things have changed and experts now argue that there is nothing like ‘the best’ age to introduce solid foods to your baby. 

If your little one shows signs that he is ready for solid baby foods, then it is time to get him started. Pediatricians encourage baby-led feeding because babies grow at different rates. Some will be ready for solids as soon as they begin hitting their 4 month old milestones while others may not be ready until they are about 7 or 8 months old. 

So, how do you know if the baby is ready for solids? Here are the signs to look for:

  • Baby opens his mouth when he sees food: If your little one opens his mouth when you put food nearby, reaches for your spoon while you put food in your mouth, or watches you intently while you eat, it might be the perfect time for solid food. 
  • Baby can hold his head up: If the baby can sit on his feeding chair, infant seat, or high chair with sufficient head control, he is ready to eat. 
  • Baby picks food from a spoon: When a baby is ready for solids, he will actively grab food from a spoon and put it into his mouth. 
  • Baby is all grown: At 4 months old, your baby has doubled his birth weight or is at least 14 pounds. Chances are his tummy is also big enough to accommodate solid foods. 

The best solid foods for a baby would be avocado, sweet potatoes, bananas, and single-grain baby cereal. But you will have to start slow. 1 or 2 ounces will be enough for a 4 month old. If the baby doesn’t seem to like the food, don’t force it. Introduce new foods now and then and be on the lookout for food allergies. 

However, you should remember that babies naturally prefer sweet foods, so make sure the foods you first introduce to baby is something he will like. It is not uncommon to see babies turn away veggies if you give them fruit first. But whatever you feed baby, ensure that it has the highest level of nutrients. 

The American Academy of Pediatrics (AAP) recommends breastfeeding your child (and not feed him on anything else) until he is about 7 or 8 months old. You can introduce solids when the baby is 6 months old but AAP still advises that baby continues breastfeeding until he is at least a year old. 

4 Month Old Sleep


When Should A 4 Month Old Go To Bed?

A 4 month old should go to bed anywhere between 6 p.m. and 9.30 p.m. By now, the baby already has a consistent sleep pattern and is probably sleeping through the night. However, these calm goodnight sessions can sometimes be interrupted by sleep regressions. Sleep regression can happen at any stage of an infant’s development but the first one mostly occurs when the newborn begins to accomplish his 4 month baby activity milestones. 

What Is 4 Month Sleep Regression Like?

A sleep regression at 4 months will shift your baby sleep patterns and get your little one sleeping for shorter stretches at night. All of a sudden, the baby who used to sleep for about 8 or 10 hours straight will start to wake up more frequently at nighttime. He will refuse to nap during the day and he will be fussier at night. 

Usually, sleep regressions are caused by a growth spurt. They are temporary and depending on the changes the baby is going through, they can last anywhere between 2 and 6 weeks. To effectively deal with sleep regressions, continue being consistent with your infant’s sleep patterns. Here are more tips on how to get baby to sleep:

  • Lay baby down awake: Teach your baby to fall asleep on his own. Don’t pick him up when he starts crying and fussing around. Continue being consistent with the tricks you had established for soothing himself to sleep. 
  • Use a pacifier: Using a baby pacifier at bedtime or during naps is a great way to get your little one to sleep better. Experts recommend pacifier use because it has been found to reduce the risk of sudden infant death syndrome

One particular 4 month old baby activity that may affect the sleep patterns of your infant is the newly acquired ability to roll over. If your baby just started rolling, you may consider going back to the swaddle blanket in case the cover he is using now comes unrolled or untucked. 

A Day In 4 Month Old Life

A child’s personality begins to shine at 4 months old, so this is a fun stage for you and your baby. Your little person will be able to express himself when he is bored, tired, or upset, and since he has already learned that doing this gets you to pick him up, the baby may sometimes express these emotions, just to get a response from you. And guess what? You are just getting started. As your little one continues to experiment and explore the world around him, more baby tricks will follow!

At this age, the baby has become more active so as you might guess, he may need more entertainment. You can try some of the following activities to keep your infant stimulated:

  • Going for a walk in a stroller so baby can see around 
  • Playing ‘peek-a-boo’
  • Hiding objects under blankets to see if the baby can find them 
  • Familiarizing baby with new toys like rattles or other objects that he can easily hold and play with 
  • Reading colorful board books together. This helps stimulate your baby’s brain.
  • Letting baby play on their belly. Put your little one on a baby play mat with a few toys and encourage him to reach for the toys.
  • Holding, singing, and talking to baby cheerfully
  • Smiling and acting excited when baby ‘talks’ and imitating his sounds so he can learn to imitate you as well

Can Babies Watch TV At 4 Months? 

No, babies cannot and should not watch TV at 4 months. The AAP advises that children at 4 months should not watch any television, as their brain is not fully developed. Infants at this age will have trouble differentiating between sounds. Televisions with high background noise are particularly bad for babies, as uncontrolled noise can be harmful to the child’s language development. 

The right age for children to start viewing TV is 18 months because, at this time, their brain has fully developed, and even then, screen time should not be more than an hour a day. 

Should You Give A 4 Month Old Your Phone?

Absolutely Not! For starters, your phone carries germs and even if you try to keep your hands clean and sanitized, you are still capable of transferring dirt and bacteria to your phone. Think about that call you received in the washroom or when you handed your phone to a friend or dropped it in the streets – you get the idea!

Baby at 4 months loves to explore with his mouth and handing him a contaminated phone would be risking his health. Don’t give baby your hone unless you have thoroughly cleaned or sanitized it, or better yet, avoid using it as a toy completely.

When Should You Be Concerned?

Every baby grows and develops differently. If you have been keeping track of your 4 month old baby activity and your little one doesn’t seem to have hit all of the above milestones, there should be no reason to worry. Your baby might just be taking a little more time to get there. However, if the baby is showing any of the following symptoms, it would be wise to consult your pediatrician:

  • Lack of interest in feeding
  • Less than 50% weight gain since birth 
  • Crossing eyes
  • Inability to hold head up
  • Inability to sit up even with support
  • Not responding to loud sounds or not showing interest in your face
  • Bulging soft spot
  • Not following people or objects as they move
  • Not smiling

My Babies Planet Overview

Baby at 4 months has developed into a completely different person. He sleeps more, he is less fussy, and he plays a lot. Welcome to the golden age mama and enjoy it while it lasts! 

Keeping track of your 4 month old milestones will help you know if your little one is growing as he should. Don’t worry if baby seems to lag a little behind – just feed him right, let him get enough sleep, and dot miss his monthly checkups.

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Hello Mother's and Father's of the world. My name is Sarah Nielsen is this is my passion MyBabiesPlanet.com, as I am a mother of two beautiful babies and they are my world. Also I love blogging and sharing my experiences of what has worked for me when raising my kids. When I'm not juggling the madness at home, or working on my blog. You will find me product researching and keeping the site freshly updated with the latest baby gear and helpful articles for my readers!