Q: At what temperature should I take my 67-day-old baby to the ER?
- Myeongchan Kim, MD
- Jul 3
- 2 min read
Updated: Jul 8
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
I heard that babies under 100 days old need to go to the emergency room if they develop a fever. At exactly what temperature should I take my baby to the ER? My older child was diagnosed with the flu recently, and my baby's temperature is slightly higher than usual, so I am very worried. My baby is 67 days old and normally has a temperature of 36.9–37.0°C, but it is currently 37.4°C.
Answer:
I understand your concern, especially with the older sibling currently recovering from the flu. It is completely natural to be extra cautious with a newborn.
Emergency Room Guidelines for Babies Under 100 Days:
38.0°C (100.4°F) or higher: If the thermometer reads 38.0°C or above, you must take your baby to the emergency room immediately.
This guideline is based on rectal or ear (tympanic) temperatures. If you are taking an armpit (axillary) temperature, you generally need to add 0.5°C to the reading to get an accurate core temperature estimate.
Because your baby is only 67 days old (under 3 months), these strict fever rules apply.
Evaluating Your Baby's Current Situation:
A temperature of 37.4°C is at the upper limit of the normal range, so it is not currently at the threshold for an ER visit. However, because there has been a known exposure to the flu and the temperature is slightly higher than your baby's baseline, very careful observation is required.
When to Seek Immediate Medical Attention:
Go to the emergency room right away if you notice any of the following:
The temperature reaches or exceeds 38.0°C (100.4°F).
The baby's feeding amount drops to less than half of their usual intake.
There are no wet diapers for 8 hours or more.
The baby shows signs of difficulty breathing, such as breathing rapidly, grunting, or their chest retracting (sinking in) with each breath.
The baby becomes unusually lethargic, limp, or excessively fussy and cannot be consoled.
Actionable Steps You Should Take Now:
Monitor the temperature: Check your baby's temperature every 2 hours. Be sure to use the same thermometer and measure in the exact same spot for consistency.
Isolate: Keep your baby as separated from the older sibling as possible. Ensure everyone in the household is washing their hands frequently and wearing masks around the baby.
Track intake and output: Keep a written record of your baby's feeding times, amounts, and the number of wet diapers.
Babies under 100 days old have developing immune systems, so taking a very cautious approach is the right thing to do. Even if your baby's temperature does not reach 38.0°C, please consult your pediatrician promptly for an in-person evaluation if you are worried or if your baby seems unwell.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
