Babies can't adjust to temperature changes as well as adults. Babies can lose heat rapidly, nearly 4 times faster than an adult. Premature and low-birth-weight babies don't have much body fat. Their bodies may not be ready to control their own temperature, even in a warm environment. Even full-term and healthy newborns may not be able to keep their body warm if the environment is too cold.
When your baby gets too cold, they use energy and oxygen to generate warmth. If their skin temperatures drop just 1 degree from the ideal 97.7°F (36.5°C), your baby's oxygen use can increase by 10%. Keeping your baby at a temperature that is not too hot or too cold helps them hold onto that energy and build up reserves. This is even more important if your baby is sick or premature.
Here are some ways babies are kept warm:
Drying and warming your baby right after birth. Wet skin can cause your baby to lose heat quickly by evaporation. They can quickly lose 2° to 3°F. It is important to warm and dry your baby right away using warm blankets and skin-to-skin contact. Another source of warmth such as a heat lamp or over-bed warmer may also be used.
Open bed with radiant warmer. An open bed with radiant warmer is open to the room air and has a radiant warmer above. A temperature probe on the baby connects to the warmer. This tells the warmer what your baby's temperature is so it can adjust automatically. When the baby is cool, the heat increases. Open beds are often used in the delivery room for rapid warming. They are also used right away in the Neonatal Intensive Care Unit (NICU) and for sick babies who need constant attention and care.
Incubator or isolette. Incubators are walled plastic boxes with a heating system to circulate warmth.
Babies will usually start out dressed only in a diaper while the heat is fully on. As the heat level is gradually reduced, more clothing is added. Once your baby is stable and can maintain their own body temperature without added heat, they are placed in an open crib or bassinet. Your baby will likely be dressed in a gown or T-shirt, a diaper, and possibly a hat. Often, a blanket or sleep sack is wrapped securely around the baby. This is called swaddling.
To lower the risk for sudden infant death syndrome (SIDS), the American Academy of Pediatrics advises that parents and caregivers not overbundle, overdress, or cover an infant's face or head. This is to prevent your baby from getting overheated. In addition, there should be no extra blankets or toys in the bed because they could block the baby's breathing.