A fever in a newborn, especially those under three months old, is a serious concern requiring prompt attention. Their developing physiological systems mean even a low-grade fever can indicate a significant underlying condition.
Defining a Newborn Fever
A newborn fever, for infants under three months old, is defined as a temperature of 100.4°F (38°C) or higher. This threshold is a medical emergency for this age group. Newborns have an immature immune system, so they may not show a strong inflammatory response to infection. Even a low-grade fever can signify a serious bacterial or viral infection.
Recognizing Other Signs
Beyond a high temperature, other signs may accompany a newborn fever. A baby might show behavioral changes like unusual lethargy or increased irritability. Feeding difficulties, such as refusal to feed or reduced intake, can also be an indicator. Parents may notice fewer wet diapers, suggesting dehydration.
Physical changes can include pale or mottled skin, or unusually flushed skin. Rapid or difficult breathing might also be observed. An unusual or high-pitched cry, different from their typical patterns, can also signal distress.
Common Causes
Newborn fevers often stem from various infections. Viral infections, like the common cold or influenza, are frequent culprits but can be serious in young infants. Bacterial infections, including urinary tract infections (UTIs) or bloodstream infections like sepsis, are more serious possibilities. Less common but severe causes, such as meningitis, an infection of the brain and spinal cord membranes, are also a concern.
Sometimes, a newborn’s temperature can rise due to overheating, such as from being overdressed or in a warm environment. While less concerning than an infection, overheating still requires attention. However, an infection is always the primary concern until ruled out.
Measuring Temperature Accurately
Accurately measuring a newborn’s temperature is important for assessing their health. For infants under three months, the most reliable method is a rectal temperature taken with a digital thermometer.
To perform this, apply petroleum jelly to the thermometer tip. Gently insert the tip about half an inch to one inch into the baby’s rectum.
Hold the thermometer until it beeps, then remove it and read the display. Other methods, such as oral, temporal, or axillary temperatures, are not recommended for newborns. These methods are less accurate and may not detect a true fever, potentially delaying medical intervention.
When to Seek Immediate Medical Care
Any fever in a newborn under three months of age requires immediate professional evaluation. Contact your pediatrician or seek emergency medical care without delay if your newborn has a temperature of 100.4°F (38°C) or higher. Communicate the exact temperature reading, the method used, and any other symptoms observed.
Prompt medical evaluation is necessary to rule out serious underlying conditions, especially severe bacterial infections that can progress rapidly. Healthcare providers will perform an assessment and may conduct tests to determine the cause. Do not use home remedies or wait to see if the fever improves, as timely intervention is vital.