A crucial part of safe sleeping is choosing the best cot mattress.
The Lullaby Trust, the UK's foremost organisation on baby safe sleeping, recommends that the safest place for your baby to sleep is on their own sleep surface, in the same room as you, for at least the first six months.
Below are some of our top tips to choose the safest mattress for your child:
Cot mattresses that comply with the current British Standards give you confidence that what you’re buying for your baby is safe, and we would always encourage you to check whether your products are marked with a BS number.
With cot mattresses it’s slightly more complicated, as there are a number of BS numbers to look out for. BS 1877-10:2011+A1:2012 is an older mandatory standard that specifies the kinds of materials, construction and dimensions required when manufacturing mattresses, while BS 7177:1996 guarantees it has passed flammability standards.
There’s also a much newer cot mattress standard called BS EN 16890:2017, which was approved in September 2017. Although it’s currently a voluntary standard, it includes a number of requirements designed to test the performance and safety of cot mattresses. This includes:
The BS EN 16890:2017 standard encompasses a wider set of tests and risks than the current mandatory standard.
We test to this standard because we believe it goes further to ensure a safe sleeping environment for babies and young children.
We test the firmness, body support and durability of each cot mattress we review, so we can recommend the best to you.
We do not recommend buying or using a second-hand cot mattress. Where possible, always buy new. This is also the advice of The Lullaby Trust.
Which? tests have found that cot mattresses can lose more than 25% of their firmness in just a few years of use. This means using a second-hand or hand-me-down cot mattress may not provide the firm support all babies need, and which reduces the risk of suffocation or smothering.
The Lullaby Trust also says there is some research that found an increased chance of sudden infant death syndrome (SIDS) when using a second-hand mattress, although the link is not yet proven.
When we surveyed 1,878 parents in February 2021 about cot mattresses, almost two in five told us they use a second-hand cot mattress.
Of these parents, 60% said the second-hand mattress was given to them, whilst the rest bought it themselves.
Cot mattress ownership:
Out of all the second-hand cot mattress bought, nine in 10 came from Facebook Marketplace, Amazon Marketplace or eBay.
Buying from an online marketplace carries some risk as you can't be certain of the history and quality of a second-hand cot mattress, meaning there is a greater chance of your second-hand cot mattress having problems.
This is backed up by our survey: around half of parents with a new cot mattress said they had issues with it, but this increases to around nine in 10 parents facing problems when the cot mattress was second-hand.
As you can see in the breakdown below, all types of problems are significantly more common in second-hand cot mattresses.
Most concerning is that a quarter of second-hand cot mattress owners reported indentations forming in the mattress or it sagging too much. A mattress that isn't firm and flat won't provide enough support for your baby, and could possibly be a suffocation risk.
As such it's vital you buy cot mattresses new, as you will have fewer issues and greater piece of mind.
Buying new doesn't have to break the bank. We compared the prices of cot mattresses that we've tested and found the average price of a Best Buy is £96, while the average price of a Don't Buy is £135!* So you don't have to spend the most money to buy the best.
If you have to buy second-hand, it's worth seeing if you can check the cot mattress yourself before parting with your money. If a reseller won't let you find out more about the history of a second-hand cot mattress, we'd advise looking elsewhere.
Use our checklist below to make sure a second-hand cot mattress (whether bought or a hand-me-down) is going to be fit for use:
*Price of cot mattresses tested by Which? as of May 2021
Sudden infant death syndrome (SIDS) is a term used to classify any sudden and unexpected death of a baby 12 months of age or younger. Sometimes referred to as 'cot death', it still isn't known for sure what causes SIDS, but there are steps parents can take to reduce the risk of it happening. Parents are urged to follow safer sleep advice when putting their baby into his or her cot. This includes:
It is very important your baby does not overheat while sleeping as the chance of SIDS is higher in babies who get too hot while sleeping.
Many cot mattress manufacturers make claims about their mattresses having extra features that provide a cooler sleeping surface for your baby, such as special construction or fabric.
It's important to know that your cot mattress won't single-handedly be able to keep your baby from overheating, so make sure you follow the temperature advice above.
Also be careful of letting marketing claims on mattresses sway your buying decision. One of the things we test cot mattresses for is insulation and we classify each mattress in terms of the level of insulation it provides.