The preterm newborn is at risk for hypothermia, defined as a core temperature of < 36.5°C. Since hypothermia causes stress to the newborn, additional interventions are needed to avoid it in the preterm newborn. Routine interventions such as drying, skin-to-skin contact, and early breastfeeding are not enough. The room’s temperature should be kept at 23–25°C, and the radiant warmer should be preheated before the preterm infant is born. One member of the delivery team places a hat on the baby as soon as they arrive. 

For babies < 32 weeks gestation, a thermal mattress covered with a blanket should be placed inside the radiant warmer. The blanket covering prevents thermal burns.

The thermal mattress is activated by squeezing the pad. The team should activate the pad at least 5 minutes before the baby is born. The mattress must be stored and activated in a room with a temperature between 19°C and 28°C. Once activated, the thermal mattress is effective for 1 hour.

Another method to support the very preterm (< 32 weeks gestation) newborn’s temperature is to wrap the baby in polyethylene plastic up to the neck area immediately after birth. The team skips drying the baby and immediately places the baby between two sheets of plastic wrap. A reclosable polyethylene bag (e.g., grocery store fruit bag) can also be used. The baby should remain fully covered during resuscitation or stabilization. A small hole can be cut in the plastic to gain access to the umbilical cord. 

The preterm baby’s body temperature must be monitored closely because warming methods can cause hyperthermia. The temperature sensor should be placed on the preterm infant and connected to the servo-control warmer. The baby’s temperature must be maintained between 36.5°C and 37.5°C.