Understanding signs of hypothermia in newborns

Hypothermia is a serious medical condition that happens when a person’s core temperature drops below 97.7°F (36.5°C), according to the World Health Organization. There are 3 stages of  hypothermia:

• Mild hypothermia: 90-95°F (32-35°C)

• Moderate hypothermia: 82-90°F (28-32°C)

• Severe hypothermia: below 82°F (below 28°C)

Thermoregulation is the body’s way of keeping its core temperature consistent. Whether it’s a hot summer day or cold out, thermoregulation keeps your core body temperature stable. Sweating and shivering are examples of how your body keeps its internal temperature stable despite temperature changes around you.

Newborns, however, can’t fully thermoregulate, which makes them more vulnerable to heat and cold. If your newborn can’t keep their body temperature up on their own, they will need help.

What causes hypothermia in newborns?

Lack of thermoregulation is a key cause of hypothermia shortly after birth since newborns aren’t yet able to keep their body temperature within the right range. 

Babies also lose heat easily and quickly because of their size, making it easier for their core temperature to change. This is especially true for newborns with low birth weight.

Research suggests risk factors for hypothermia include: 

• Premature birth

• Birth via C-section

• Low birth weight

• Being born into a cold delivery or operating room

Are there ways to prevent hypothermia in newborns?

Cold temperatures are especially concerning after birth when many newborns are delivered into cold delivery or operating rooms. The best way to prevent hypothermia in newborns is to keep any room the newborn is in at the right temperature. WHO recommends keeping the delivery room between 77.0 and 82.4°F (25-28°C) at a minimum. Skin-to-skin contact shortly after birth also helps keep your baby warm. 

What are the complications of hypothermia in newborns?

Hypothermia can have serious consequences, especially for preterm infants. Possible complications include:

• Low blood sugar levels (hypoglycemia)

• Bleeding in the brain (hemorrhage)

• Lung and breathing issues

Is "cold stress" the same as hypothermia?

Cold stress happens when the body’s core temperature is 96.8-97.5° F (36-36.4° C). Cold stress should be considered a warning sign. If your baby’s temperature continues to drop, they may develop hypothermia, which is dangerous. 

Normal body temperature vs. low body temperature in newborns

Body temperature can change slightly throughout the day and still be considered “normal.” According to the American Academy of Pediatrics (AAP), the following are average body temperatures, depending on what part of the body the temperature is taken:

• Rectal temperature: average 98.6°F (37°C), but can be as low as 96.8°F (36°C) and still be considered normal

• Oral temperature: average 97.6°F (36.5°C), but can be as low as 95.8°F (35.5°C) and still be considered normal

A rectal measurement is the most accurate when checking a newborn's temperature.

Signs and symptoms of hypothermia in newborns

Hypothermia is a medical emergency and can lead to death. If you think your baby might have hypothermia or a low body temperature — or if their rectal temperature reading is less than 97.7°F (36.5°C) — call 911 for immediate medical help. 

Other than a low body temperature, a baby with hypothermia may:

• Appear sluggish and less active than usual

• Have a weak cry

• Have pale, cold, or cool skin

• Have trouble breathing

• Have a low appetite or may not eat well

• Have low energy

Serious symptoms of hypothermia include a weak pulse and irregular breathing. But remember: any symptoms of hypothermia should be taken seriously, and you should get emergency medical help.

Treating low body temperature in newborns

Treating a newborn with hypothermia involves rewarming them in an incubator or under a radiant warmer. You’ve likely seen this type of equipment in hospital delivery rooms or NICUs. If your baby’s hypothermia is caused by an underlying medical condition, it should be treated too.

Newborns with hypothermia should also be monitored for complications of hypothermia like low blood sugar, low oxygen, or trouble breathing. If these conditions, or others, occur, they should be treated. 

Hypothermia in newborns: key takeaways

With the right measures in place — such as keeping your baby warm, staff maintaining delivery and operating rooms at the recommended temperature, and lots of skin-to-skin bonding time — most babies do well and do not experience complications of hypothermia.  

If your baby becomes hypothermic, warming them gradually will be critical. Get medical help immediately if your baby has a low body temperature. 

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