How Long Can You Use a Co-Sleeper

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If you decide to use a co-sleeper with your newborn through that first year then there are a number of growth and physical development milestones that you will need to pay attention to ensure safer use.

In this article, we will discuss what these milestones are for the various types of co-sleepers so you have a better understanding of how long you can use your co-sleeper.

Co-Sleeper Design Definitions

The length of time that your baby can use a co-sleeper will depend on the type of product you are using.

Below are the two main design categories and we will discuss each separately throughout the article:

  • In Bed Co-Sleeper – Positioned on the bed with you and is basically a small bed with crib bumpers intended to prevent you from rolling on top of your baby.
  • Bedside Co-Sleeper – Acts as an extension of your bed to create separate sleeping areas.

You can read more about each category of co-sleeper here.

Co-sleeper design variations

Co-Sleeper Limitations

There are two key developmental stages when a co-sleeper or loungers can become unsafe for an infant:

  1. They outgrow the size of your co-sleeper. This can happen anywhere from 3-12 months depending on the size of your co-sleeper (usually 25″ – 34″ in length).
  2. They are strong enough to sit up straight in the co-sleeper (~6 months). This introduces risk which we will cover below.

The above are general guidelines only. All babies develop at a different pace and you will need to pay attention to how your child behaves when in the co-sleeper.

Why Sitting Up in a Co-sleeper is Unsafe

Your baby will show you very quickly if they are capable of moving themselves out of position in a co-sleeper. As soon as they are able to do so you should consider progressing to a crib or bassinet.

The level of risk associated with sitting up is different depending on the design category:

In Bed

The whole purpose of a co-sleeper is to keep your baby in a safe place when sharing a bed with you. When they are strong enough to sit up and move around then there is a risk that they fall out.

This could see them land in a dangerous position. However, the risk of suffocation is low as they are now strong enough to move themselves around.


A bedside co-sleeper poses an additional risk due to the potential falling over the side rails. Three out of the four sides will lead directly to the floor.

Crawling in any direction other than toward the bed will result in a fall that could be very dangerous.

What to Do when Baby Outgrows the Co-sleeper

If your baby outgrows a bedside co-sleeper then you have two options:

  1. Continue co-sleeping with your child in the same bed.
  2. Stop co-sleeping and transition to a crib.

Your choice depends entirely on your circumstances and how prepared you are to see through the transition to a crib.

Some parents may opt to continue co-sleeping in bed (especially if breastfeeding frequently through the night).


We encourage all parents to err on the side of caution when co-sleeping. As soon as you notice the capacity to get into an unsafe position then it may be time to stop using the co-sleeper and graduate to a crib.

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James is our general tech. guy, product testing extraordinaire, and loving father of one. He has been with since 2016 and has a hand in most of the content on the site.

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