(Pictured: baby sleeping in 100% Bamboo Baby Blanket (Swaddle Blanket) - Little Gulls design)

For new parents, monitoring baby’s body temperature can be a real worry as evidence suggests that the chance of Sudden Infant Death Syndrome (SIDS) is higher in babies who get too hot. The Lullaby Trust advises that the best way to make sure your baby does not get too hot is to sleep them on a firm, flat surface, on their back, with bedding and clothing that is suitable for the correct room temperature. 

This article pulls together a list of common FAQs around temperature management with links to advisory sources - we hope you find it useful.

What temperature should a baby’s room be at night?

The Lullaby Trust recommends that any room a baby sleeps in should be between 16°c and 20°c - a room thermometer can help you do this.
Remember that the safest place for your baby to sleep is in the same room with you (in a separate cot or moses basket) for the first six months – this makes it easier to manage room temperature but also allows you to frequently check baby's body temperature.
A large study of evidence from across Europe found that the risk of sudden infant death was significantly reduced when the infant slept in the same room, but not the same bed, as the parents.

What clothes should baby sleep in?

Baby should sleep in a baby sleeping bag or well-fitted sheets and baby blankets. If you are using sheets and baby blankets they should be tucked in carefully with no loose ends which might obstruct baby's breathing. If you are using baby sleeping bags, make sure that they are comfortable and well-fitted around the neck and arms so that baby can't wriggle down inside. Never use duvets, pillows or quilts for babies under 12 months. The best way to adjust your baby's temperature is by adding or removing layers - remember that a folded baby blanket counts as two layers and provides twice the insulation. Your baby should only need to wear a nappy, a sleep vest and sleepsuit to sleep in. Never put your baby in hats or gloves to sleep, even if they have done so in a Neonatal Intensive Care Unit.

What is the normal temperature for a baby?

A normal temperature for a baby (measured under the arm) is around 36.4⁰C. This may vary slightly depending on the time of day and what your child has been doing. A fever is usually considered to be a raised temperature of 37.5⁰C (99.5⁰F) or above.

How do I know if baby is too hot while sleeping?

The best way to check on your baby’s temperature is by putting your hand on the skin on their tummy or the back of their neck. Don’t use their hands or feet as a guide as they will always feel cooler than the rest of their body.

How do I take baby’s temperature?

The best way to get a fast, accurate reading is to use a digital thermometer - these are readily available to buy online, at the pharmacy and in most large supermarkets.

To take your baby's temperature:

  • hold them comfortably on your knee and put the thermometer in their armpit – always use the thermometer in the armpit with children under five

  • gently but firmly, hold their arm against their body to keep the thermometer in place for however long it says in the manufacturer's instructions

  • the display on the thermometer will then show your baby's temperature

How do I know if baby is too hot?

You will know if baby is too hot if their skin feels hot, clammy or sweaty. If your baby is too hot you will need to remove some layers.
Babies who are unwell with a cold or fever will need fewer, not more bedclothes.

Why do babies who are unwell need fewer layers?

Babies who are unwell need fewer layers so that they have the opportunity to lower their body temperature. If your baby shows signs of being significantly unwell you should seek medical advice.

My home is below the ideal temperature in the winter, should I keep the heating on all night?

It is rarely necessary to keep your heating on all night - adding an extra layer will usually help. Remember that babies should never wear hats whilst sleeping as their head will help them maintain their body temperature by releasing heat.

If you do feel your home is too cold and you want to leave the heating on all night, make sure it is set at a low temperature, and certainly no higher than 20⁰C.

Will my baby overheat if swaddled? 

Your baby may become overheated if he is covered with too many layers. If the weather is particularly warm, dress your baby in only a nappy before swaddling

The Lullaby Trust (formerly FSID) also site the following recommendations for safe swaddling:

  • Use thin materials

  • Do not swaddle above the shoulders

  • Never put a swaddled baby to sleep on their front

  • Do not swaddle too tight

  • Check the baby's temperature to ensure they do not get too hot

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