Fever in Newborn Guidelines

A fever in a newborn is typically defined as a body temperature of 100.4°F (38°C) or higher when measured rectally.

You should seek medical attention immediately if your premature infant is younger than 3 months and has a fever of 100.4°F (38°C) or higher or if they show signs of distress such as lethargy, difficulty breathing, or persistent crying.

Common causes of fever in newborns and young infants include infections (such as colds, flu, or urinary tract infections), reactions to immunizations, and overheating due to excessive clothing or environmental heat.