Co-sleeping
UK guidance does not simply tell parents never to bed share. It identifies circumstances that are never safe, and explains how to reduce risk otherwise.
Never share a bed with your baby if
You or anyone else in the bed smokes, wherever or whenever they smoke, or your baby was exposed to smoking in pregnancy. The Lullaby Trust counts smoke exposure in pregnancy here, and it is the condition most often left off lists like this one.
You or anyone else in the bed has recently drunk any alcohol, or taken any drugs or medication that make you feel sleepy.
Your baby was born prematurely, before 37 weeks of pregnancy, or weighed under 2.5kg, which is 5.5 pounds, when they were born.
Never fall asleep on a sofa or armchair with your baby. The Lullaby Trust says this significantly increases the risk of sudden infant death, because a baby can easily slip into a position where they are trapped and cannot breathe. It applies to every family without exception.
The Lullaby Trust calls bed sharing in these situations very dangerous, and says that then it is always best to put baby in their own sleep space. The NHS words the same conditions as a plain instruction not to. Your health visitor or midwife can advise on your own situation.
The distinction that gets blurred
Room sharing means the baby sleeps in their own cot or Moses basket in the same room as you. Both the NHS and the Lullaby Trust say it should be that way for every sleep, day and night, for at least the first six months.
Bed sharing means the baby sleeps in the same bed as an adult. This is what most people mean by co-sleeping, and it is the one carrying the conditions above.
The two get conflated constantly, which matters because the recommended practice and the conditional one are different things.
Why the guidance is framed this way
UK safer sleep guidance is deliberately practical rather than absolute, because a large proportion of parents bed share at some point, frequently unplanned, and frequently while feeding at night.
Telling parents simply never to do it risks a worse outcome: an exhausted parent who intended to stay awake falls asleep feeding on a sofa, which is considerably more dangerous than a prepared bed.
So the guidance names the circumstances in which bed sharing is very dangerous, which is the Lullaby Trust phrase, and then explains how to make a bed safer for the situations where sharing happens anyway. Nothing in that second part makes an adult bed the equal of a separate sleep surface in your room, which is still what the guidance recommends.
If you do share a bed
Assuming none of the very dangerous circumstances above apply:
Keep the baby on their back, as always, for every sleep. The Lullaby Trust is blunt about the alternative: sleeping a baby on their front or side greatly increases the risk of sudden infant death.
Keep pillows, duvets and adult bedding away from the baby. Adult bedding is a suffocation and overheating risk. The baby should not be under your duvet.
Make sure the baby cannot fall out or become trapped in the bedframe, the headboard, or the gap between the mattress and a wall. The Lullaby Trust goes further and says to remove slatted or decorated headboards altogether.
Never leave your baby alone in an adult bed. The Lullaby Trust states this separately and it is easy to miss, because an adult bed is only a shared sleep surface for as long as the adult is in it.
Do not sleep with the baby between two adults, and keep other children and pets out of the bed.
A firm, flat mattress. Not a waterbed, not a very soft mattress, and no memory foam surface the baby can sink into. The Lullaby Trust gives the test: your baby's head should sink no more than a few millimetres into a mattress.
Keep the baby away from the pillow area and do not let them sleep on a pillow.
What the baby's own sleep space needs
Whether in your room or theirs, safer sleep guidance is consistent.
On their back, every sleep, night and day.
A firm, flat mattress protected by a waterproof cover, in good condition, with no raised or cushioned edges or sides, fitting the cot or Moses basket properly with no gaps. The two-finger gap test repeated all over the internet, and previously on this page, is not in the Lullaby Trust or NHS guidance, so the standard to work to is simply no gap.
A clear sleep space: no pillows, duvets, cot bumpers, pods, nests, sleep positioners, weighted or bulky bedding, rolled-up towels or anything soft on top of the mattress. A well-fitting baby sleeping bag or firmly tucked sheets and blankets instead. The Lullaby Trust puts a figure on the cost of getting this wrong: soft or bulky bedding such as quilts, pillows and duvets has been shown to increase the risk of sudden infant death threefold.
Feet to foot, with the baby's feet at the end of the cot, if using sheets and blankets.
A room between 16 and 20 degrees, which is the range the NHS and the Lullaby Trust both give, and a smoke-free environment. A room thermometer is the only way to know it rather than guess it.
Pillows are not used in a cot at all. The sourced threshold is the Lullaby Trust one: soft or bulky bedding, pillows and duvets among it, is not recommended for babies under 12 months. Past that, no UK body publishes an age at which a pillow becomes safe, so in practice it waits until the child is out of a cot and into a bed, and later is fine. The firmer figure this page carried before was not sourceable and has gone.
Night feeding, realistically
The highest-risk scenario is falling asleep somewhere unplanned.
Prepare the bed before you are tired, on the assumption you might fall asleep, rather than relying on staying awake.
Feed in bed rather than on a sofa or armchair if there is any chance of dozing off, because sofa sleeping carries a far higher risk.
Put the baby back in their own space when you have finished, if you are able to.
The Lullaby Trust states that any amount of breastfeeding reduces the risk of sudden infant death syndrome, and also that a formula-fed baby's risk comes down by following the rest of the advice. Everything above applies regardless of how you feed.
Where to get proper advice
What you have just read is a summary of somebody else's guidance. The expertise behind this site is mattresses, beds and bedding, not paediatrics, so every safety point above is taken from the Lullaby Trust and the NHS and attributed where it is used. Read it as a route to those two sources rather than as advice about your own baby.
The Lullaby Trust publishes the UK safer sleep guidance in full and has a helpline. Your health visitor or midwife can discuss your circumstances, including if you are bed sharing and want to do it as safely as possible.
One thing not to buy as a safety measure. The Lullaby Trust states that there is no research showing baby monitors help prevent sudden infant death, that a monitor can never replace a parent or carer's supervision of a baby, and that movement monitors will not work reliably while you are co-sleeping. A monitor is a convenience. It is not a substitute for any of the above.
Asking is not an admission of anything. Health visitors would far rather have the conversation than have parents making it up alone at 3am.
Related reading
A line worth drawing here. Everything above comes from the Lullaby Trust and the NHS and costs nothing to follow. Everything below is this site's own shopping coverage, and some of those links earn a commission. Buying from one of them changes nothing about the guidance, and no product sold anywhere reduces the risk of sudden infant death.
Where the guidance comes from
Shopping guides: cots and mattresses
Before and after
How this site works
Nothing here is paid for by a brand. No manufacturer has copy approval, a preview, or the ability to change a score, and where a link earns a commission that never changes a ranking.
Where a brand does not publish a specification, that is stated rather than estimated, because an absent number is itself information. The corrections log and the products I will not recommend page are both public.
Questions people ask
Is co-sleeping safe?
The Lullaby Trust calls bed sharing very dangerous if anyone in the bed smokes, if the baby was exposed to smoking in pregnancy, if anyone in the bed has recently drunk any alcohol or taken drugs or sleepy-making medication, or if the baby was born before 37 weeks or weighed under 2.5kg. Never fall asleep with a baby on a sofa or armchair, which applies to everyone.
What is the difference between room sharing and bed sharing?
Room sharing means the baby sleeps in their own cot in your room, which UK guidance recommends for at least six months. Bed sharing means the baby is in the adult bed, which is the conditional practice.
How do I bed share more safely?
Keep the baby on their back, away from pillows and adult bedding, not between two adults, with no gap in the bedframe or headboard they could be trapped in, on a firm flat mattress, and never left alone in the bed. None of it applies if any of the very dangerous conditions are present.
What should a baby's cot contain?
Nothing but a firm, flat mattress with a waterproof cover, fitting the cot with no gaps, and a well-fitting baby sleeping bag or firmly tucked sheets. No pillows, duvets, cot bumpers, pods, nests, sleep positioners or weighted bedding.