mattress for bassinet

Are Supplemental Bassinet Mattresses a SIDS Risk?

Oct 11, 2021

Are Supplemental Bassinet Mattresses a SIDS Risk?

AHEAD: Everything you need to know about whether to buy a mattress for a bassinet.

Figuring out where your baby will sleep can be tricky. You’ve probably got lots of questions…

Do all bassinets come with mattresses—or do you need to buy one separately (like you do with a crib)?

Are bassinet mattresses always so thin and firm? Would it be safe to use a thicker one instead?

What about adding additional padding on top of the mattress that comes with the bassinet? Could that increase the risk of SIDS?

If these are some of the questions on your mind, you’re in the right place.

mattress for bassinet

This guide will answer common questions about bassinet mattresses.

And unlike the vast majority of others on the subject, this guide is based on scientific evidence, not personal anecdotes or opinions.

Below, you’ll see what the CPSC, the AAP, and bassinet manufacturers have to say.

Let’s dive in!

bassinet mattress safety

Do all bassinets come with mattresses?

All bassinets that meet federal safety standards are sold with a mattress included.

This means that you do not need to purchase a bassinet mattress separately.

The ASTM F2194 standard regulates the following in regard to bassinet mattresses:

  • Sleeping pad thickness and dimensions. This is intended to prevent suffocation or asphyxiation as a result of gaps between the sleeping pad and non-rigid sides of a fabric or mesh bassinet.
  • The flatness of a segmented mattress. This is intended to prevent asphyxiation associated with “V” shapes that can be created by the segmented mattress folds.

In short, when you purchase a regulated bassinet, it comes with a mattress that has passed safety testing by a third-party CPSC-approved laboratory.

Why are bassinet mattresses so thin and firm?

Bassinet mattresses are specially designed to prevent suffocation in two notable ways.

They are firm to prevent air pockets from being formed around the baby’s head.

When exhaled air collects in pockets near the infant’s airway, it increases the chance of rebreathing and suffocation—particularly if the baby rolls onto their side or belly.

They are thin to prevent entrapment—which is of particular concern in bassinets with flexible sides.

When an infant bed has flexible sides (i.e. mesh), it’s especially important for the mattress pad to be thin.

The CPSC has warned (in regard to Pack N Play mattresses) that infants can become wedged between the mattress and the wall of the structure if the mattress is too thick.

playard mattress danger

Source: CPSC

Is it safe to swap out the mattress that came with your bassinet?


Critically, the mattress that came with your bassinet was safety tested with the bassinet as a unit.

Replacing a bassinet mattress is akin to swapping out the buckles on your child’s car seat with something ‘more comfortable’ you found online. Both are introducing untested variables.

Here is a warning from a bassinet user manual.

bassinet mattress warning

All regulated bassinets manuals contain similar warnings.

Is it safe to add a mattress topper to a bassinet?

As you’ve probably surmised by reading the previous sections of this article, the answer is no.

It is never safe to add a mattress topper to a bassinet—or anything to make the bassinet more comfortable, for that matter.

The AAP explicitly states,

“Mattress toppers, designed to make the sleep surface softer, should not be used for infants younger than 1 year.”

Anyone who advises you to purchase a supplemental mattress for a bassinet is either unfamiliar with the unscientific evidence—or is trying to sell you something.

Bassinet Mattress FAQs

How often should you replace bassinet mattress?

A bassinet mattress does not typically need to be replaced since babies use bassinets for such a short window of time.

That said, if you think the structure of the mattress has been compromised, or if it smells musty from being in storage, it may be time to replace it.

Important: Only order a replacement mattress directly through the manufacturer (not through Amazon or similar) and be sure to provide your exact bassinet model number.

What size is a bassinet mattress?

Bassinet mattresses come in all different shapes and sizes.

(This is different from regulated full-size cribs, which all take the same mattress size.)

As we’ve discussed in this article, you should ONLY use the mattress that came with your bassinet.

Do not purchase a replacement or supplemental mattress—even if it has the same dimensions as your current mattress pad.

If you need a replacement mattress, order it directly through the manufacturer (not through Amazon or similar) and be sure to provide your exact bassinet model number.

What type of bassinet mattress is best?

The best bassinet mattress is the firm mattress that comes with your bassinet.

There aren’t any significant differences between bassinet mattresses, since they are regulated for safety.

Can I make my own bassinet mattress?

Never make your own bassinet mattress. Only use the mattress that came with your bassinet.

For your baby’s safety, it’s important that they sleep on a mattress that has been profesionally tested with the bassinet as a unit. (This testing is done by a CPSC-approved third-party lab).

Can I put a blanket in a bassinet?

The evidence is clear that loose bedding in an infant’s sleep space is a suffocation risk.


It doesn’t matter whether the blanket is over or under your baby—both are unsafe.

Keep your baby warm by using a wearable blanket such as a swaddle or a sleep sack.

Are bassinet mattresses safe?

Yes, bassinet mattresses are safe—assuming they are used as intended by the manufacturer.

As long as the bassinet is completely empty with no toys, blankets, loveys, or extra padding, it is considered a safe sleep space for your baby.

Does the Halo bassinet come with the mattress?

Yes. All models of the HALO Bassinest come with a mattress. (The same goes for all regulated bassinets).

You do not need to purchase a separate bassinet for the HALO.

Final thoughts on buying a mattress for a bassinet

As you’ve now seen, not only is it unnecessary, but it’s unsafe to buy a separate mattress for a bassinet.

All regulated bassinets come with their own mattress pads that have been safety tested with the bassinet as a unit.

Bassinet mattresses are intentionally thin and firm to reduce the risk of suffocation and entrapment. Soft mattresses increase the risk of SIDS and other sleep-related death.

It’s never safe to add a mattress topper or any sort of padding that makes a bassinet mattress more comfortable.

Supplemental Mattress for Bassinet: Safe? Necessary?