A temperature of 38°C or higher in a baby under three months needs prompt medical assessment
For a baby under three months, a temperature of 38°C requires prompt hospital assessment. Do not watch at home or give fever medicine first and wait. Serious bacterial illness at this age can present with fever alone, so looking reasonably well is not enough reassurance. Babies under 8 days are outside the cited guideline and especially need urgent assessment.
What it takes
Consultation and testing may cost a few hundred RMB in China.
What you may gain
The American Academy of Pediatrics has a dedicated guideline for well-appearing, full-term febrile infants aged 8–60 days, defining fever as ≥38.0°C and using separate pathways for 8–21, 22–28 and 29–60 days. Infants younger than 8 days are outside its scope; the source emphasizes immediate assessment for them too.
Context & considerations
Serious bacterial infection can manifest only as fever at this age. “Still seems alert” is not a reason to wait, nor should self-administered antipyretics delay care.
Research & references
Pantell RH, Roberts KB, Adams WG, et al. (2021). Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old. Pediatrics, 148(2), e2021052228. https://doi.org/10.1542/peds.2021-052228