For new parents, few things are as alarming as a warm forehead or flushed cheeks on a baby. A fever in infants can raise all kinds of questions: Is this serious? Should I give medicine? Do we need to go to the hospital?
The truth is, fever is not always a sign of danger. In many cases, it’s simply your baby’s immune system doing its job. But in babies under one year of age, especially newborns knowing when to take a fever seriously can make all the difference.
What Is Considered a Fever in Babies?
In infants, a body temperature above 38°C (100.4°F) taken rectally is considered a fever. Anything between 37.5°C and 38°C (99.5°F to 100.4°F) is often referred to as a “low-grade” fever or elevated temperature.
Unlike in older children or adults, even mild fevers in babies under three months should always be evaluated by a doctor, as their immune systems are still developing and infections can progress rapidly.
Why Do Babies Get Fevers?
Fever is not an illness it’s a symptom, and often a healthy response to infection. Common causes of fever in infants include:
- Viral infections (like a cold or mild flu)
- Post-vaccination immune response
- Teething (though this usually causes only slight temperature elevations)
- Bacterial infections (e.g., urinary tract infections, ear infections)
- Overheating due to overdressing or a hot room
It’s also important to note that not all temperature elevations are due to infection. Sometimes babies can become warm due to external factors, like being bundled up too tightly or spending time in a hot environment.
When Is a Fever in Babies Dangerous?
While some fevers are harmless, certain red flags demand immediate medical attention:
- Newborns (0–3 months) with a temperature of 38°C (100.4°F) or higher
- Persistent fever lasting more than 24 hours in infants under 6 months
- Fever over 39°C (102.2°F) in babies between 3 and 12 months
- Lethargy, refusal to eat, weak cry, or unusual sleepiness
- Difficulty breathing, bluish lips, or rapid breathing
- Convulsions or seizures
- Rash that doesn’t fade when pressed
- Vomiting or diarrhea combined with fever
Always trust your instincts if your baby seems unwell or “not quite right,” don’t wait to consult a healthcare provider.
How to Take Your Baby’s Temperature Correctly
For babies under 12 months, rectal thermometers are the most accurate. Other methods like forehead strips, underarm readings, or ear thermometers can be inconsistent in this age group.
Here’s how to measure a rectal temperature safely:
- Apply a small amount of baby-safe lubricant to the tip of the thermometer.
- Lay your baby on their back or stomach and gently insert the thermometer about 1.3–2.5 cm (0.5–1 inch) into the rectum.
- Hold it in place until the thermometer signals it’s done.
- Clean the thermometer thoroughly after use.
Never estimate a fever based on how warm your baby feels to the touch. Hands are not thermometers.
Should You Give Fever-Reducing Medication?
Not all fevers require treatment. Fever is part of the body’s defense mechanism, and lowering it too quickly can sometimes delay recovery. However, if your baby seems uncomfortable, isn’t feeding well, or struggles to sleep due to the fever, infant acetaminophen (paracetamol) may be used but only after consulting a doctor, especially for babies under 3 months.
Avoid giving ibuprofen to infants under 6 months, and never give aspirin to children due to the risk of Reye’s syndrome.
At-Home Care for Babies with Fever
If your pediatrician has ruled out serious causes and recommends home monitoring, here are some supportive measures:
- Keep your baby hydrated with breastmilk or formula. Dehydration can occur quickly during fever.
- Dress your baby lightly and keep the room comfortably cool.
- Offer comfort and cuddles skin-to-skin contact can soothe both baby and parent.
- Check temperature regularly, but don’t obsess over the numbers alone. Behavior is just as important.
Most low-grade fevers resolve within a day or two, especially if due to a viral infection or a vaccine reaction.
Fever Is a Signal, Not a Sentence
In most cases, fever in babies is not an emergency, it’s communication. It’s your baby’s immune system saying, “I’m working on it.” Still, infants are vulnerable, and early intervention matters. Knowing when to observe and when to act is one of the most important skills a parent can learn.
If you’re ever in doubt or need professional evaluation, the pediatric specialists at Erdem Hospital are here to guide you with compassion, clarity, and medical precision tailored to your baby’s needs.