10 Newborn Health Red Flags Every Parent Should Know and Act On Immediately

3. Newborn Health Red Flag: Fever (High or Low Temperature) Warning Signs

The Problem

A newborn’s body temperature is a key indicator of well-being. Their temperature regulation isn’t fully developed, making them susceptible to both overheating and hypothermia. According to pediatric guidelines, a rectal temperature of 100.4°F (38°C) or higher, or below 97.5°F (36.5°C) in an infant under three months is considered abnormal.

High fever could be the first visible symptom that your baby’s immune system is fighting off an infection—bacterial or viral. Conversely, a low temperature may indicate a problem with regulating body heat, which can be just as concerning. Additionally, newborns often don’t show typical signs of illness beyond variations in temperature. This is why vigilant monitoring is so important.

The Solution

1. Accurate Temperature Monitoring: Always use a digital thermometer for more precise readings. For newborns, rectal and forehead (temporal) measurements tend to be the most accurate, but confirm which method your pediatrician recommends and follow instructions carefully.
2. Create a Warm, Comfortable Environment: Keep your baby’s room at a moderate temperature (68–72°F or 20–22°C) and dress them in layers that can be removed or added for comfort.
3. Hydration and Feeding: A fever can lead to fluid loss and dehydration. Offer breast milk or formula more frequently. If you suspect dehydration due to fever, seek medical advice.
4. Call Your Pediatrician: If your baby’s temperature reading is above 100.4°F (38°C) or below 97.5°F (36.5°C), contact a healthcare professional and follow their instructions. They may advise an in-person visit immediately, especially if other symptoms are present.

By staying alert to temperature changes, you’re catching early signs that your newborn’s body might be battling an underlying issue. When in doubt, err on the side of caution.