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How To Dress a Baby Under a Swaddle, Sleep Bag, and Sleep Suit

It’s important to dress your child safely for sleep. But what does a baby wear underneath a swaddle, sleep bag, or sleep suit? From how many layers a baby should wear for sleep to what a baby shouldn’t wear under a swaddle, find out everything you need to know below. 

What should a baby wear underneath a swaddle or sleep bag?  

What your baby wears underneath a swaddle or sleep bag depends on several factors: the weather, season, and their unique needs. At Love To Dream™, our multi award-winning sleep solutions are designed to empower families to make the right decisions for their child’s needs. Every baby feels hot and cold differently to each other and temperatures can fluctuate throughout the day/night. 

Below, discover the most important factors to consider when dressing your baby for sleep.  

Layer according to the temperature and season 

We recommend layering sleepwear according to the temperature and season as it allows you to easily remove/add a layer or two when required. Below, find examples of how to dress your child safely for sleep in summer and winter.

How to dress your baby for sleep in summer 

During hot weather, choose a low Temperature rating when purchasing a Swaddle Up™, Transition Bag or Suit. A single layer might be enough, but if your child needs more warmth, you can add an extra layer such as a short sleeve/ sleeveless and legless romper or bodysuit underneath.  

With envelope necklines and clever twin zippers, our new layers range is designed to be layered, changed, and washed with ease. You can find our summer sleep solutions here.

How to dress your baby for sleep in winter  

Our bestselling Swaddle Up™ is made from a lightweight, breathable stretch cotton blend and comes in a range of ratings for different temperatures. During the colder months, we recommend dressing your child in a full-length romper/bodysuit or bodysuit and leggings depending on the temperature. You can find our winter sleep solutions here. 

You can find further examples of how to dress your baby for sleep in our temperature guide.

Consider the change in temperature  

Temperatures can fluctuate throughout the day and night so make sure to take this into consideration when choosing layers and Temperature ratings. 

When selecting sleepwear for your baby, consider the below: 

  • Always choose lightweight and breathable sleepwear. Our romper and PJ collection is designed to be layered with ease depending on the season and temperature to keep your little one safe and comfortable during sleep. 

  • Make sure sleepwear is the correct size for your child’s age, height, and weight. 

  • When swaddling, make sure the swaddle is made from lightweight and breathable fabric. Our award-winning Swaddle Up™ comes in a range of Temperature ratings for different seasons and temperatures.  

What shouldn’t a baby wear underneath a swaddle? 

It’s important to dress your baby according to the room temperature. Always follow the below safe sleep guidelines when dressing your baby for sleep:  

  • Children regulate their body temperature through their face and head, never put your child to sleep wearing a hat, beanie or bonnet.   

  • Choose clothing that is the correct size for your child’s age, height, and weight, and in accordance with the temperature of the room.   

  • Never leave any loose layers, pillows, blankets or toys in their sleep space. 

  • Always put your child to sleep on their back with their face and head uncovered on a firm, flat, and clean mattress that is the correct size for the cot or bassinet.   

You can learn more about safe sleep guidelines here or on the Lullaby Trust website.  


Should babies wear anything under a swaddle?  

If your child is warm and comfortable, they do not need to wear anything but their nappy underneath a swaddle. However, it’s important to dress your child according to the temperature.  

For example, a short-sleeve and legless bodysuit or romper is ideal during the warmer months while a long-sleeved/long-legged romper will ensure they are warm during winter.  

You should always choose a swaddle, sleep suit, or sleep bag based on the temperature. At Love To Dream™, we have a range of options available to suit different seasons.  

The importance of layering with swaddles and sleep bags 

A swaddle, sleep bag, and sleep suit count as one layer. You can then layer a lightweight romper, bodysuit, or PJs underneath depending on the temperature and season. When choosing sleepwear, consider the Temperature rating to ensure it is suitable. The higher the Temperature rating, the warmer it is. The lower the Temperature rating, the lighter it is. 

For example, our  Swaddle Up™ Extra Warm is designed for temperatures between 14° and 16° while the Swaddle Up™ Warm is suitable for temperatures between 16° and 20°.

UK Update Clothing Guide

How many layers should a baby wear under a swaddle? 

There is not a recommended number of layers that a baby should wear under a swaddle. How many layers a baby wears under a swaddle depends on the temperature, season, and baby’s specific needs.  

Important: never layer swaddles, this increases the risk of suffocation and overheating.  

What temperature should your baby be at night? 

It’s important to follow the below steps:  

  • Always dress your baby according to the room temperature and season, you can use our temperature guide to find the right sleep garment.  

  • Never leave toys, pillows, or blankets where the baby is sleeping. 

  • Babies control their temperature through their face and head. Make sure to put your baby to sleep on their back with the face and head uncovered.   

  • Never use hot water bottles or heated blankets.   

If concerned, you can check your baby’s temperature to ensure they’re comfortable. You can do this by feeling your child’s back or tummy, which should be warm.  

Can I layer sleep bags to increase the warmth?  

We do not recommend layering swaddles, sleep bags, or sleep suits, as this can increase the risk of overheating or suffocation - which can lead to sudden infant death syndrome (SIDS). Instead, choose an appropriate garment for the room temperature and if necessary, lightweight layers that can be worn underneath.  

At Love To Dream™, we know that every child is different, and we’re committed to helping you to find the right solution for your family. With you at every step of the journey, Love To Dream™ believes today’s little dreamers are the shapers of tomorrow. For further advice from our experts, please visit our blog.