How to Choose a Safe Cot Mattress: EU Safety Standards Explained

A cot mattress might seem like a simple purchase, but it’s one of the most safety-critical items you’ll buy for your baby. Your newborn will spend up to 16–18 hours a day sleeping on it, and the wrong choice can carry genuine risks. Knowing how to select a safe cot mattress EU safety standards baby compliant product requires understanding what certifications actually mean, which materials to avoid, and how to ensure a proper fit — because an ill-fitting mattress is a hazard regardless of its quality. This guide distils the latest European safety standards and NHS Safe Sleeping guidance so you can make a confident, well-informed choice.

EU Safety Standards: What to Look For

In the European Union and the UK, cot mattresses sold for babies are subject to specific safety standards. The key standard to know is EN 16890:2017, which covers mattresses intended for use in cots and cribs for children under 3 years. This standard sets requirements for:

• Firmness (resistance to compression) — a critical safety factor
• Size and dimensional tolerances — to ensure proper fit in the cot
• Waterproofing and water resistance properties
• Flammability resistance
• Chemical restrictions, including limits on formaldehyde, heavy metals, and certain flame retardants

In the UK post-Brexit, the UKCA mark has replaced the CE mark for products placed on the UK market from January 2023. For most practical purposes, products carrying CE or UKCA markings have been assessed against the same underlying technical standards. When buying online from EU retailers, look for the CE mark; for UK retailers, look for UKCA.

Beyond the basic EN standard, look for additional certifications that indicate higher levels of chemical testing:

• OEKO-TEX Standard 100: Tests for over 100 harmful substances and certifies that every component of the mattress — including covers, fillings, and adhesives — is free from harmful chemicals at levels that could affect health
• CertiPUR: Specifically relevant for foam-core mattresses; certifies that the foam is made without certain flame retardants, heavy metals, and other harmful chemicals
• Soil Association organic certification: For mattresses marketed as organic, this UK certification verifies genuine organic content

Firmness: The Most Critical Safety Factor

Mattress firmness is the single most important safety characteristic for infant mattresses. The NHS Safe Sleep guidance (aligned with Lullaby Trust recommendations) is unambiguous: baby mattresses must be firm and flat. A mattress that is too soft allows a baby’s face to sink into it, increasing the risk of suffocation and potentially contributing to Sudden Infant Death Syndrome (SIDS).

Test a mattress for firmness by pressing the centre firmly with your hand. When you remove your hand, it should spring back immediately with no visible impression. A mattress that retains the shape of your hand impression is too soft for a baby.

Memory foam mattresses — despite their popularity for adult sleep — are not recommended for babies under 12 months precisely because they conform to the shape of the head and face. The same applies to pillow-top or cushioned-top mattresses. Firmness is not about comfort in the adult sense; it is about safety.

Size and Fit: Why Gaps Are Dangerous

A mattress that doesn’t fit the cot properly is a serious hazard. If there is a gap between the mattress edge and the cot frame, a baby can become wedged in it — a risk of entrapment and suffocation. The standard cot mattress sizes in the UK and Europe are:

• Standard cot: 60 x 120 cm
• Standard cot bed: 70 x 140 cm
• Moses basket: Varies; always measure before buying

The gap between the mattress and any side of the cot should be no more than 2.5 cm (about one finger’s width). Measure your cot carefully before purchasing, and if buying second-hand furniture, measure both the internal cot dimensions and the mattress separately — never assume they match.

Materials: Foam, Sprung, and Natural Options

The main mattress types available in European markets each have different characteristics:

Open-coil or pocket-sprung: Traditional spring-based mattresses offer good firmness, durability, and breathability. They tend to be heavier and more expensive but last well if properly cared for.

Foam: Lightweight and often more affordable. Look for high-density foam (at least 22 kg/m³) and CertiPUR or OEKO-TEX certification. Avoid ultra-cheap foam mattresses, which may use lower-grade materials and chemical binders.

Natural fibre (coir, wool, latex): Mattresses with natural fillings such as coconut coir or organic wool are popular in eco-conscious European markets and tend to be naturally breathable. Ensure any natural latex used carries OEKO-TEX or equivalent certification, as latex can contain volatile organic compounds if poorly processed.

Breathable/airflow mattresses: Products marketed as having enhanced breathability claim to reduce the re-breathing of exhaled air if a baby’s face turns into the mattress. The Lullaby Trust notes that while some studies suggest potential benefit, there is currently insufficient evidence to recommend these over standard firm mattresses.

Frequently Asked Questions

Should I buy a new mattress for each baby?

The Lullaby Trust and NHS Safe Sleep guidance recommend buying a new mattress for each baby, or at minimum a mattress that is clean, dry, and in excellent condition. The basis for this recommendation is research suggesting a small increased risk of SIDS associated with using a second-hand mattress from outside the family home, though the mechanism is not fully understood. If budget is a significant constraint, a clean, well-maintained mattress from a previous sibling in the same household carries lower risk.

Do I need a waterproof mattress cover?

A waterproof or water-resistant cover is highly practical, but ensure it fits snugly with no loose folds or wrinkles. A bunched-up cover can create surface irregularities that compromise safety. Some mattresses have a waterproof layer built into the cover — this is fine as long as the mattress itself remains firm.

What about travel cot mattresses?

Many travel cots come with very thin, foldable mattresses that do not meet the firmness standards for regular overnight use. If your baby regularly sleeps in a travel cot, consider purchasing a firmer-grade travel cot mattress that meets EN 16890 requirements. Occasional use with the original travel cot mattress is generally considered lower risk.

How do I maintain a cot mattress?

Air the mattress regularly, use a waterproof cover, and clean any spills promptly. Avoid storing the mattress under the cot base where air cannot circulate. Most mattresses should be replaced if they show signs of significant compression, sagging, or structural damage.

Your Practical Next Step

When buying a cot mattress, use this quick checklist: CE or UKCA marked; firm and flat (no memory foam); correct size with less than 2.5 cm gap to cot sides; OEKO-TEX or CertiPUR certified if foam; bought new or from within your family. The Lullaby Trust website (lullabytrust.org.uk) is the definitive UK resource for safe sleep guidance and is updated as new evidence emerges.

Don’t overlook the wider sleep environment once the mattress is sorted. The NHS Safe Sleep guidelines also recommend placing babies on their back to sleep, keeping the cot clear of pillows, duvets, bumpers, and soft toys, and maintaining a room temperature of around 16–20°C. A firm, well-fitting mattress is the foundation of a safe sleep space, but it works best as part of a complete safe sleep setup. Taking fifteen minutes to review the full Lullaby Trust guidance before your baby arrives — or as soon as possible if they’re already here — is time very well spent.