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15 Oct 2021

Six in 10 cot mattresses have issues that could be a safety risk

The risk of problems increases if you're using a second-hand cot mattress for your baby
crying baby in cot

The majority of parents from a Which? survey said they had issues with their cot mattress, some of which could be a serious safety risk.

The proportion of cot mattresses with problems increased if it was second-hand.

Read on to find out what the main problems are, why they matter, and how Which? testing can help you find a cot mattress that won't be a risk to your child.

Which cot mattress should you buy? - our comprehensive guide to getting the best one for your baby

The most common issues with cot mattresses

In February 2021, Which? asked 1,878 parents with children aged up to five years if they'd experienced any issues with their cot mattresses. A staggering six in 10 said they had.

Breaking this stat down into parents with a new cot mattress and those with a second-hand one, we found almost half of parents with a new mattress had problems but this rises to almost nine in 10 for second-hand owners.

The problems parents described aren't trivial either, some present serious safety risks for your child.

IssueThe associated safety riskNew cot mattresses owners with this issueSecond-hand cot mattresses owners with this issue
Gap(s) between the mattress and cot bed frameA trapped limb in the gap could cause an injury10%24%
Indents forming on the cot mattress during useMattress not being firm enough and could be a suffocation risk for a newborn baby9%25%
Zips on mattress covers breakingZip being small enough to potentially be a choking risk if your child swallows it11%27%

The table shows the percentage of parents whose cot mattress has had these issues. On average, around one in 10 new cot mattresses had one of these safety risks, while this increases to one in four if the mattress is second-hand.

For the full list of issues parents reported, go to our cot mattress and baby bedding safety guide

At Which? we do not recommend buying a cot mattress second-hand, and the survey evidence agrees - there is a much greater chance of it having a problem with a serious safety risk associated with it.

Which? cot mattress safety tests

which cot mattress durability test

We take safety seriously at Which?, and our cot mattress safety tests go above and beyond to ensure it will provide a safe nights sleep for your baby.

We test to the current cot mattress safety standard (BS EN 16890:2017 + A1:2021). While it's voluntary, meaning cot mattresses are not required to meet it to be on sale, manufacturers are strongly encouraged to meet it to reduce the risks and hazards for babies and young children.

Our tests check for the following:

  • Choking and swallowing hazards - such as loose zips or stickers
  • Entrapment hazards - such as a cot mattress being too small or covers shrinking after washing, which could lead to a gap between the mattress and cot bed frame where a limb could get trapped.
  • Suffocation risks - such as the mattress not being firm enough, both in its new condition and after a durability test that simulates years of use.

If a cot mattress we test doesn't pass the requirements set out by the safety standard, we don't recommend it.

You can be certain that a recommendation from Which? means the cot mattress meets the safety standard and provides a supportive, comfortable nights sleep for your little one.

Best Buy cot mattresses - read our reviews on the products that aced our tests

Buying a second-hand cot mattress

hand pressing down on cot mattress

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.

Buying new doesn't mean buying expensive. In fact, the average price of a Best Buy cot mattress is £95.75 whereas a Don't Buy is £135.29.* It's cheaper to be safer!

However, if you have to buy second-hand it is essential you take a few extra steps to make sure the mattress won't be a safety risk down the line. Always ask if you can check the cot mattress yourself before paying. If a reseller won't let you then we advise you don't buy from them.

Use this simple check list to make sure the second-hand cot mattress is fit for use:

  1. Test it is still firm, with no holes or tears - when you press down the mattress should resist and spring back immediately after you remove your hand.
  2. Measure it's dimensions, to make sure there will be no gaps - take a tape measure and check the length and width in several locations on the mattress. The standard UK cot bed is 140cm x 70cm, but double-check the size your cot bed needs beforehand.
  3. Check if it was previously protected by a waterproof cover- this will reduce the chance of unhealthy germs lurking in the mattress. We recommend you clean the mattress and leave it to air-dry thoroughly before reusing it.

* Average prices correct as of 7 October 2021