The short answer
At four months, your baby may smile, respond to your voice with sounds, examine their hands and hold their head more steadily. These are examples of skills the CDC sees in most babies; they do not all have to appear on the same day.
In this guide · 11 sections
Keep in mind
- Smiling, chuckling and responding with sounds may appear now.
- Looking at hands, holding toys and steadier head control are examples of movement development.
- Four-month milestones are not a test, and variation is not a diagnosis.
- Discuss loss of skills or continuing developmental concerns with your pediatrician.
What do four-month milestones really mean?
At four months, your baby’s smiles, turning toward your voice and close inspection of their hands offer glimpses into different parts of development. These skills do not have to appear together. One day your baby may reach toward a toy; another day, they may prefer watching your face.
The CDC’s four-month milestones describe skills seen in at least 75% of babies by that age. The checklist is not a test, a diagnosis or a timetable every baby must follow precisely. Watching how your baby changes over time tells you more than a single attempt.
Smiles and connection with you
Your baby may smile spontaneously to get your attention and chuckle when you play together. These sounds need not be full, sustained laughter yet. Looking at you, moving excitedly or making sounds while you talk can be an early effort to keep the exchange going.
During a diaper change, for instance, your baby may smile back when you smile. At other times they may turn away when tired. That does not mean they do not want to connect with you; they may simply need a break.
The sounds your baby makes and hears
Four-month-olds often make vowel-like cooing sounds such as “ah” and “oo.” When you respond and your baby makes another sound, you are already taking turns in a conversation. Turning toward your voice is another skill that may emerge now.
You do not need to expect actual words. A few short phrases, face-to-face conversation and a pause to let your baby answer are enough to play with sounds. Noisy toys and constant background screens cannot replace this close interaction.
Exploring hands and surroundings
Your baby may gaze at their hands and bring them to their mouth. Holding a lightweight toy placed in their hand, or swinging an arm toward a toy nearby, are also examples of the CDC’s four-month milestones.
Opening their mouth on seeing the breast or bottle near feeding time can show that your baby recognizes a familiar routine. Hands in the mouth alone do not necessarily mean hunger or teething; at this age, mouthing is also a way to explore.
Head control and tummy time
When held upright, your baby may keep their head steadier without extra support. During awake tummy time, they may push up onto their elbows and forearms to lift their chest. These movements let your baby see the world from new angles.
Rolling, sitting without support and crawling are not requirements for every four-month-old. Try not to turn later motor skills into a scorecard for this month. Tummy time is only for when your baby is awake and supervised; always place them on their back to sleep.
What can you do today?
When your baby is calm and alert, lean close, make a gentle sound and pause for a response. Imitating their sound helps them experience the rhythm of taking turns. You could also look at a sturdy picture book together or sing a short song.
On a safe floor mat, place a large, light toy within reach without pressuring your baby to grab it. Offer several short opportunities for supervised tummy time throughout the day. Stop if your baby becomes upset or tired, and try again later.
What if skills appear at different times?
Two babies born in the same month may be interested in very different games. Sleep, hunger, surroundings and mood all affect what you happen to see. A skill that does not appear on one try should not immediately be labeled something your baby cannot do.
If your baby was born early, development may need to be considered using corrected age. The CDC advises using corrected age with its checklist for babies born more than three weeks prematurely. Your pediatrician can help account for any individual medical circumstances.
When should you talk to your pediatrician?
Tell your pediatrician promptly if your baby loses a skill they previously had. Ongoing concerns about eye contact, responding to sounds, head control or movement also deserve discussion. Not seeing one item yet does not automatically mean there is a problem.
You can describe what you noticed, when it began and whether your baby used to do it. Your clinician may recommend a standardized developmental screening; online checklists do not replace one. The goal is support when needed, not a competition between babies.
When to seek support
Some signs need emergency help; other concerns can be discussed with your child’s healthcare team.
- Loss of a skill the baby previously had
- Persistent concerns about responses to sounds, interaction or movement
Sources used for this guide
- CDC — Milestones by 4 Months
- Centers for Disease Control and Prevention (CDC) — 4 Month Online Milestone Checklist
- American Academy of Pediatrics / HealthyChildren.org — HealthyChildren – How Active is Your Baby? – 4 Eylül 2025
- CDC — Milestones In Action: By 4 Months
English editorial review:
The English text and regional guidance have been checked editorially. This is not an individual clinical assessment.
Luluna provides general parenting information. It does not diagnose conditions or replace your child’s healthcare professional.
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