Laughing, rolling practice and the famous sleep shift
Chuckles are turning into laughs, toys are being grabbed on purpose, and rolling may be on the way. Sleep often gets bumpier around now — it's a normal developmental shift, not something you've broken.
Development
Most babies this age hold their head steady when upright, swing at dangling toys, and grip one when you put it in their hand. Everything heads straight to the mouth — that's how babies explore.
You'll likely hear lots of cooing, and sounds made back at you when you talk. Chuckles are common; full belly laughs may follow soon.
Some babies attempt their first roll (usually front to back) around now; many wait weeks or months longer. Both are normal.
The 4-month sleep shift
Around 4 months, babies' sleep matures into adult-like cycles — the AAP notes that regular sleep cycles only emerge at about this age. More stirring between cycles means more wakings, which is why sleep can suddenly feel worse.
It's often called a regression, but it's really progression — the new sleep architecture is permanent, and babies gradually learn to link cycles themselves.
Keeping nights calm, dim and a bit boring helps, as does an unhurried, repeatable wind-down. Most families find the bumpiest patch passes within a few weeks.
Rolling and safety
Stop any arms-in swaddling at the very first signs of rolling — a baby who rolls while swaddled can't push themselves back.
Once rolling starts, never leave your baby on a bed, sofa or changing table even for a second; a mat on the floor is the safe spot for nappy changes.
Keep putting your baby down on their back for every sleep. If they roll themselves over once they can roll both ways, you don't need to keep flipping them back — but always start them on their back, in a clear cot.
And you
Broken sleep on top of months of broken sleep is genuinely hard. Share the load where you can, lower the bar on everything non-essential, and remind yourself this phase passes.
Your baby staring longingly at your dinner isn't a sign to start solids yet — the NHS notes that fist-chewing, extra night waking and wanting more milk are often mistaken for readiness. Around 6 months is still the mark.
If the 16-week vaccinations were missed, they can be caught up any time — just ring your GP surgery.
Feeding at this stage
Pick how you're feeding — we'll remember for next time. Every one of these is a good way to feed a baby.
Breastfeeding
- Distractibility often starts around now — your baby pops on and off to look at every noise; a quiet, dim room for some feeds can help.
- Shorter daytime feeds may be balanced by more evening or night feeding for a while — that's your baby topping up, not your supply failing.
- Extra night waking during the sleep shift isn't always hunger; feeding back to sleep is fine if it works for you, and so is trying other soothing first.
Breast + expressed
- Bottle feeds get distractible too — a calm corner away from the action helps your baby focus.
- Try not to drop pumping sessions too quickly during the sleepy chaos; supply is easiest to keep than to rebuild.
- Keep rotating the freezer stash — oldest milk first.
Breast + formula
- More night waking around now is often the sleep shift rather than hunger — settling first is fine, and so is feeding; you know your baby.
- Protect the breastfeeds that matter most to you — for many that's morning and bedtime — and let the rest flex.
- There's no need to change your mix because of a rough sleep patch; consistency usually helps more than switching things around.
Formula
- Waking more doesn't automatically mean needing bigger bottles — follow your baby's appetite at each feed.
- There's no need for 'hungry baby' milk — the NHS is clear that first infant formula is the only formula your baby needs for the whole first year.
- Keep feeds responsive: offer breaks, watch for turning away, and let your baby decide when they're done.
Totally normal (even when it doesn't feel it)
- Sleep suddenly falling apart after a settled patch — the 4-month shift is developmental and temporary.
- Rolling only one way, or not at all yet — the range is wide.
- Nap refusal and contact naps — many babies this age only nap on a person, and that changes with time.
- Intense interest in watching you eat — it's curiosity, not a signal to start solids early.
- Baby hair thinning or a bald patch at the back of the head — it grows back.
- A day of feeding constantly followed by a day of barely bothering.
Worth checking
You know your baby best — if any of these ring true, or something just feels off, it's always OK to ask.
- Your baby can't hold their head steady when you hold them upright.
- They don't make sounds back when you talk to them, or don't coo at all.
- They don't bring their hands to their mouth.
- They don't push up onto their forearms during tummy time.
- They don't watch things as they move, or one eye turns in or out most of the time beyond this age.
- They feel very stiff or very floppy.
- If any of these sound familiar, mention them to your health visitor or GP — it's always OK to get your baby checked, and most checks end in reassurance.