4 month old baby

Parenting: 4-Month-Old Babies' Developmental Milestones

Parenting tips for your 4-month-old.


Once their babies turn 4 months old, many parents start breathing easier. With the sometimes scary newborn stage behind them, parents can now rest easier and enjoy the increasingly social, active and communicative little individuals their babies have become.

Learn more about caring for your 4-month-old baby with these tips for this new stage of parenting.

4-month-old milestones: social and emotional

Your 4-month-old is becoming more attuned to the world around them and is eager to engage with others.

Some key social and emotional milestones to look out for include:

  • Spontaneous smiling: Your baby will begin to smile back at you and interact with genuine delight. Encourage your baby's sociability by smiling, making eye contact and speaking in a soothing tone.
  • Imitative play: Your baby is imitating your actions and facial expressions, indicating they can better understand and react to social signals. 
  • Playing to learn: By now, your baby enjoys playing with others and may become upset when playtime ends. Give them plenty of chances to have fun exploring with you, other caregivers or friends. Introduce your baby to new experiences and turn everyday activities into opportunities to play.

Language and communication milestones at 4 months

By the fourth month, your baby is getting better at using sounds and expressing emotion to tell you what they want.

Some important language and communication milestones to observe include:

  • Differentiated crying: Your baby's cries may change depending on their needs, like if they're hungry, tired, uncomfortable, or in pain. Pay attention to your baby's cues and respond promptly to their signals, providing comfort and reassurance as needed.
  • Babbling and vocalization: Your baby will start to babble and coo, experimenting with different sounds and vocalizations. Encourage their language development by responding to their sounds with enthusiastic verbal responses, creating a playful and interactive dialogue.
  • Responsive interaction: Your baby is becoming more attentive and responsive to your voice and gestures. Take advantage of this by talking to your baby during everyday routines and activities. Narrate your actions and engage them in conversation about what you do together.

4-month-old milestones: brain development

Your baby's brain is rapidly growing and developing, laying the foundation for future learning and cognitive leaps.

Some key brain development milestones to observe include:

  • Object recognition: Your baby will begin to recognize familiar objects. They will also have gotten better at recognizing people from far away. These changes show their eyesight and ability to make connections are improving.
  • Hand-eye coordination: Your baby's hands and eyes work together better, making it easier for them to grab things. Support their hand-eye coordination by offering age-appropriate toys and activities that encourage reaching and grasping. Now is a good time to give them toys and other things they can safely manipulate.
  • Emotional expressiveness: Your baby is becoming more expressive and communicative, letting you know if they're happy, sad, or content. Watch your baby's face and body movements, and respond with love, affection and understanding to their feelings.

4-month-old milestones: movement and physical development

At 4 months old, your baby is moving around more. As they explore their surroundings, they will delight you and themselves with all their new tricks! Better able to hold their heads up, babies now have an easier time looking around and enjoying the world.

Some important movement and physical developmental milestones to look for include:

  • Hand-to-mouth coordination: Your baby will start bringing their hands to their mouth, exploring objects and textures through touch and taste. Encourage this natural behavior by providing safe and age-appropriate toys for your baby to grasp and explore.
  • Pushing up: Your baby can lift themselves up using their elbows while on their stomach. Help babies get stronger by continuing to give them tummy time. Pushing up with their arms helps build babies' muscles and improves their coordination and overall development.
  • Rolling over. Babies may start rolling over from their stomach to their back or vice versa, showing better movement and coordination. Help them get plenty of practice on a play mat or a blanket on the carpet. Now that they are more mobile, you'll want to make sure they will be safe wherever they roll.

Food and nutrition milestones for 4-month-old babies

As your baby continues to grow and develop, their nutritional needs evolve. At 4 months of age, babies exhibit significant changes in their eating habits. Now that they can hold more food in their stomachs, they can eat slightly more and a little less frequently. 

Some important food and nutritional milestones to look for

  • Accelerating growth: According to the American Academy of Pediatrics, many babies double their birth weight by about three to four months. 
  • Longer time between feedings: By 4 months, breastfed and bottle-fed babies can easily go four to five hours without eating. While some babies may still wake up for nighttime feedings, it's perfectly normal if they don't. Unless your pediatrician says otherwise, there's no need to wake your baby for feeding.
  • Clearer hunger signals: A baby sucking on their first often means it's time to eat. Feed your baby when they seem hungry. Offering them breast milk or formula on demand will help them grow healthy and strong.

Your baby's sleep patterns at 4 months

By 4 months, infants have typically established a consistent sleeping schedule. They can now sleep for a longer stretch. Between naps and nighttime, many babies sleep as many as 16 hours per day.

Two daytime naps are common, and to parents' delight, many babies at this age can sleep through the night. As their circadian rhythm develops and matures, these patterns become more established.

4-month-old milestones: things to look out for

Every baby develops differently. Yet it's important to watch for signs that they might need extra help or evaluation.

Some things to watch out for in your 4-month-old include:

  • Eye movement issues: Difficulty moving one or both eyes in any direction may indicate vision problems. Seek a healthcare provider's advice.
  • If your baby doesn't smile at people or respond to social cues, talk to your pediatrician about any concerns.
  • Motor skills delays: Your baby should be able to put their hands in their mouth. They should also be able to push down with their legs on a hard surface and make cooing sounds. If they aren't, it's with checking in with your pediatrician.

The fourth month of your baby's life is an exciting time filled with growth, exploration, and discovery. By understanding each step and giving the right support, you can help them reach their full potential.

Now that you have spent four months getting to know your baby, trust your instincts. But don't ever hesitate to seek expert advice if you have questions. By being careful, curious and loving, you are paving the way for your child's development for years to come.


4-month-old Lucyana snuggles with her mom. © UNICEF/UNI412329/Wong
4-month-old Lucyana snuggles with her mom. © UNICEF/UNI412329/Wong