Fever in a Baby Under 3 Months: Why It Is Always an Urgent Call
How to take an accurate temperature, what counts as a fever, and why any fever in a young infant needs same-day medical evaluation.
For older children, a fever is usually a sign the immune system is working. For a baby under three months old, it is different: a young infant's immune system is still developing, so any fever needs prompt evaluation.
What counts as a fever
- A rectal temperature of 100.4 F (38 C) or higher is a fever in an infant.
- Rectal temperature is the most accurate method under three months.
- Forehead and ear thermometers are not reliable enough at this age.
- Do not give fever medicine before calling; we want to know the true temperature.
What to do right away
Call our office immediately, day or night, if your baby under three months has a temperature of 100.4 F or higher. After hours, our answering service reaches the on-call physician. If your baby is limp, difficult to wake, breathing hard, or has blue or gray coloring, call 911.
Other symptoms that need urgent attention
- Refusing several feedings in a row.
- Far fewer wet diapers than usual.
- A rash that does not fade when pressed.
- Persistent, high-pitched, or inconsolable crying.
Preventing infection in the early weeks
- Ask visitors to wash hands and stay home when sick.
- Keep your baby away from crowded indoor spaces early on.
- Make sure caregivers are up to date on flu, COVID-19, and Tdap vaccines.
- Breastfeeding, when possible, passes along protective antibodies.
When to call Divaker Pediatrics
Our Mount Dora office is here for questions big and small. Call 352-383-8386 to schedule a visit, or use the healow patient portal to send a message to our team. If your child has a medical emergency, call 911.