Baby at 4 months
Updated 25 Oct 2026
Skills most babies can do at 4 months
Social and emotional
- Your baby can smile spontaneously, especially at people around them
- Your baby likes playing with people and may cry if you stop playing
- Your baby copies some of your movements and facial expressions, such as smiling or frowning.
Language and communication
- Your baby starts to babble, moving their mouth to make sounds even though they don't mean anything yet. So adorable, parents!
- Your baby practises showing expressions and tries to copy the sounds they hear
- Your baby cries in different ways to show they are hungry, in pain, tired or bored
Cognitive (learning, thinking and problem-solving)
- Your baby lets you know when they are happy or sad
- Your baby responds to affection
- Your baby can reach for a toy with one hand
- Your baby can use hands and eyes together, such as looking at a toy and reaching for it
- Your baby follows moving things with their eyes from side to side
- Your baby can look straight at your face up close
- Your baby recognises familiar people and objects at a distance
Movement / Physical development
- Your baby can hold their head steady without support
- When their feet are placed on a hard surface, your baby can push down with their legs
- Your baby can roll over from tummy to back
- Your baby can hold and shake toys, and loves exploring and swinging dangling toys
- Your baby brings their hands to their mouth
- When placed on their tummy, your baby can push up on their elbows and lift their upper body off the floor. Your baby is really strong!
If your baby shows any of the signs below, take them to see a doctor soon
- Your baby doesn't watch things as they move
- Your baby doesn't smile at people
- Your baby can't hold their head steady
- Your baby doesn't coo or make sounds
- Your baby doesn't bring things to their mouth
- Your baby doesn't push down with their legs when their feet touch a hard surface
- Your baby has trouble moving one or both eyes in all directions
Things you can do for your 4-month-old
- Hold and talk to your baby; smile and be cheerful during this time
- Try to set a regular schedule for your baby's feeding and sleeping.
- Pay close attention to what your baby likes and doesn't like; you'll learn how to meet their needs and how to make them happy.
- You can copy the sounds your baby makes
- Always show excitement and smile when your baby makes sounds
- It's wonderful if you set aside quiet playtime to read or sing to your baby.
- Give your baby age-appropriate toys, such as rattles or colourful pictures
- Play games such as peekaboo with your baby
- Don't forget to keep your baby safe as they reach for toys and explore their surroundings
- Try holding toys close so your baby can reach for them or kick at them
- You can put toys or rattles in your baby's hand and help them hold on.
- Hold your baby upright with their feet touching the floor, and sing or talk to them as they “stand” with your support
Signs that need a doctor now
If you notice any of the signs below, please go to the nearest health facility to be checked by a doctor.
Bluish skin around the lips, hands and feet, or the whole body
A bluish colour around the lips, on the hands and feet, or over the whole body is a sign the baby is short of oxygen. Call 115 or take your baby to the nearest hospital at once.
Difficulty breathing, fast breathing, chest indrawing
Breathing faster than 60 breaths a minute, chest indrawing, flaring nostrils or pauses in breathing are signs of breathing difficulty in a newborn. This sign needs to be checked by a doctor. Please take your baby to the nearest health facility now. If the baby stops breathing or turns blue, call 115.
Convulsions (fits) in a baby
A convulsion in a young baby is a danger sign. Call 115 or take your baby to the nearest hospital at once; lay the baby on their side and do not put anything in the mouth.
Signs of dehydration
No wet diaper for 6 hours, a dry mouth and lips, and few or no tears when crying are signs of dehydration. Sunken eyes, a sunken soft spot, cold hands and feet and excessive sleepiness are signs of severe dehydration and an emergency. Please take your baby to the nearest emergency department now or call 115.
Source: Vinmec – Mất nước ở trẻ sơ sinh
Fever of 38°C or higher in a baby under 3 months
A baby under 3 months with a temperature of 38°C or higher needs to be seen by a doctor, even if the baby seems otherwise well. Please take your baby to the nearest health facility now.
Jaundice spreading to the belly, arms and legs, or appearing early
Jaundice that spreads to the belly, arms, legs, palms or soles, appears within the first 24 hours after birth, or lasts more than 2 weeks needs to be checked by a doctor. Please take your baby in now, especially if the baby is feeding poorly or very sleepy.
Source: Bệnh viện Đa khoa Tâm Anh – Cách chăm sóc trẻ sơ sinh bị vàng da
Poor feeding, lethargy, hard to wake
Feeding problems, clearly reduced activity, or a baby who feels cold are danger signs in a newborn. This sign needs to be checked by a doctor. Please take your baby to the nearest health facility now.
Fever after birth
A temperature of 38°C or higher after giving birth can be a sign of infection. This sign needs to be checked by a doctor. Please go to the nearest health facility now.
Source: CDC – Hear Her: Urgent Maternal Warning Signs and Symptoms
Heavy bleeding after birth
Soaking through one or more pads in an hour, or passing large clots, is a sign that needs emergency care. Call 115 or have someone take you to the nearest hospital now.
Source: CDC – Hear Her: Urgent Maternal Warning Signs and Symptoms
Thoughts of harming yourself or your baby
You are not alone, and these thoughts need a doctor's support soon. Please tell someone you trust right away and go to the nearest health facility today. If you feel unsafe right now, call 115.
Source: CDC – Hear Her: Urgent Maternal Warning Signs and Symptoms
Sources
Content advised by our doctors.
- CDC – Milestones by 4 Months | Learn the Signs. Act Early. | CDC (accessed 22 Oct 2026)
- HealthyChildren.org (AAP) – Checkup Checklist: 4 Months Old - HealthyChildren.org (accessed 22 Oct 2026)
- Vinmec – Sự phát triển của trẻ từ 1-6 tháng sau sinh | Vinmec (accessed 22 Oct 2026)
- Source for the signs that need a doctor: Vinmec – Triệu chứng suy hô hấp ở trẻ sơ sinh
- Source for the signs that need a doctor: WHO – Newborn mortality (fact sheet)
- Source for the signs that need a doctor: Vinmec – Mất nước ở trẻ sơ sinh
- Source for the signs that need a doctor: Vinmec – Trẻ bị sốt, khi nào cần đưa đi khám?
- Source for the signs that need a doctor: Bệnh viện Đa khoa Tâm Anh – Cách chăm sóc trẻ sơ sinh bị vàng da
- Source for the signs that need a doctor: CDC – Hear Her: Urgent Maternal Warning Signs and Symptoms
This article helps you understand and prepare. It does not replace a check-up. For an answer about your own situation, please ask the doctor who is caring for you.