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4 Month Old Baby: Milestones, Sleep and Feeding

Your 4 month old baby: laughing, rolling, reaching for toys, the 4 month sleep regression and getting ready for solids.

Before you use this guide: Every baby grows and develops at their own pace, and healthy babies vary a lot. Weights are WHO medians at the start of the month, not targets. If your baby was born early, use their corrected age. This is general information, not an individual medical assessment.

How your baby is developing

At four months your baby is much more engaged with the world. They can hold their head steady when upright, push up on their elbows and forearms on their tummy, bring their hands to their mouth and swing an arm at a toy. Many hold a toy for a short time if you put it in their hand.

They are also getting chattier. You may hear chuckles that are not yet full laughs, and sounds like “ooo” and “aah”. They will make sounds back when you talk to them and turn towards your voice. Many babies learn to roll from tummy to back around now, though some do it later.

Milestones to look for

These are skills that many babies show around this age. Some will come earlier and some later, and missing one is not usually a cause for worry.

• Smiles on their own to get your attention
• Chuckles when you try to make them laugh
• Looks at you, moves or makes sounds to keep your attention
• Makes cooing sounds, and sounds back when you talk
• Turns their head towards the sound of your voice
• Opens their mouth when they see the breast or bottle if hungry
• Looks at their hands with interest
• Holds their head steady without support when held
• Holds a toy when you put it in their hand, and swings at toys
• Brings their hands to their mouth, and pushes up on elbows or forearms on their tummy

For the full checklist, see the CDC milestone checklist for this age.

Feeding

• Breast milk or formula is still all your baby needs. Health services recommend waiting until around six months to start solids, and not before about 17 weeks.
• Babies of this age are often more easily distracted during feeds, and may feed less often but more efficiently.
• Signs that your baby is not ready for solids include a strong tongue-thrust reflex and not being able to sit with support.
• Teething can begin from around four months, though many babies have no teeth until later.

Sleep

• Many babies go through a change in sleep around four months, often called the four-month sleep regression. Their sleep cycles become more adult-like, so they wake more easily. It usually passes within a few weeks.
• Wake windows are getting longer, around one and a half to two and a half hours.
• Keep a consistent, calm bedtime routine, and put your baby down drowsy but awake if you can.
• Stop swaddling once your baby can roll, and use a sleeping bag instead.

See our wake windows by age guide and the rules in our safe sleep guide.

Play and learning

• Offer rattles and soft toys that are easy to grasp.
• Play on the floor on a blanket, with toys just out of reach to encourage reaching.
• Talk to your baby about what you are doing and wait for their response.
• Sing songs and play simple games like peekaboo.
• Let your baby look at themselves in a baby-safe mirror.

Keeping your baby safe

• Your baby could roll off a bed or changing table at any moment. Keep one hand on them or change them on the floor.
• Anything your baby can grab will go in their mouth, so keep small objects, jewellery and cords out of reach.
• Use a sleeping bag rather than loose blankets.
• Never leave your baby alone with a pet or young child.

Looking after yourself

Broken sleep can be especially hard if the regression hits. Share night duties if you can, and nap when you have the chance.

Your baby may be teething or changing in other ways, so keep talking to other parents and your health visitor for reassurance.

When to ask for help

Talk to your doctor or health visitor if your baby does not smile, does not follow things with their eyes, does not hold their head up or bring their hands to their mouth, seems very stiff or floppy, or loses skills they had before. Seek urgent help for breathing difficulties, a rash that does not fade under a glass, or a baby who is very drowsy or hard to wake.

Trust your instincts. If you are worried about your baby at any age, contact your doctor, health visitor or local emergency number.

This content is for general information only and is not medical advice. Every pregnancy and every baby is different. Always talk to your doctor, midwife or paediatrician about your own situation, and seek urgent care if you are worried.