What is the best thermometer to use for babies?

Best Thermometer for Babies

For babies, rectal thermometers are the most accurate method for temperature measurement, but axillary (underarm) thermometers provide a good balance of accuracy, safety, and comfort for routine temperature monitoring in healthy infants.

Types of Thermometers for Babies

Rectal Thermometers

• Considered the gold standard for measuring temperature in neonates and young infants by the American Academy of Pediatrics 1
• Provides the most accurate core temperature reading, which is critical for detecting fever in newborns 1
• However, rectal thermometry carries risks including discomfort, potential for rectal perforation, and cross-contamination 2
• Electronic rectal thermometers like the Penguin thermometer have shown comparable accuracy to traditional mercury-in-glass thermometers with faster measurement times 3

Axillary (Underarm) Thermometers

• Recommended as a safe and reliable alternative to rectal thermometry for healthy neonates 2
• Research shows axillary measurements do not significantly differ from rectal temperatures in healthy newborns, with means differing only by 0.02°F 2
• Demonstrates better reliability between measurements compared to rectal thermometry 2
• The most stable of body-temperature reading methods with no outliers 4

Temporal Artery Thermometers

• Non-invasive and better tolerated by infants than rectal thermometry 5
• However, they have limited sensitivity (66%) for detecting fever in infants 5
• Temporal artery thermometers typically display higher mean temperatures than rectal thermometers by about 0.25°F 2

Tympanic (Ear) Thermometers

• Less accurate than axillary thermometers in infants 5
• Lower sensitivity (49%) for detecting fever compared to temporal artery thermometers 5
• Not recommended as primary temperature measurement in very young infants 1

Temperature Measurement Guidelines

For Newborns and Young Infants

• Body temperature should be maintained between 36.5°C and 37.5°C after birth through admission and stabilization 6
• Admission temperature of newly born nonasphyxiated infants is a strong predictor of mortality and morbidity at all gestations 6
• Hypothermia in newborns is associated with serious morbidities, including respiratory issues, hypoglycemia, and late-onset sepsis 6

For Older Infants

• The American College of Radiology defines fever as a temperature of ≥38°C/100.4°F 1
• Verify the accuracy of home temperature measurements and document a rectal temperature in the clinical setting for infants and young children 1

Recommendations Based on Age

For Neonates (0-28 days)

• Rectal temperature is the most accurate method for critical temperature assessment 1
• Axillary temperature is a safe, accurate, and reliable alternative for routine monitoring in healthy neonates 2

For Infants (1-12 months)

• Rectal thermometry remains the standard for accurate fever detection 1
• Axillary thermometry provides good accuracy with less discomfort 2
• Temporal artery thermometers can be used for screening but have limited sensitivity for detecting fever 5

Common Pitfalls to Avoid

• Relying on less reliable methods such as tympanic membrane temperatures or chemical dot thermometers when accurate temperature measurements are critical 6
• Using inconsistent temperature measurement methods, which can yield significantly different readings 7
• Failing to consider that not all infections manifest with fever, particularly in very young infants 7
• Overlooking the impact of recent antipyretic use on temperature readings 1

Summary

For routine home monitoring of healthy babies, an electronic axillary (underarm) thermometer offers the best combination of accuracy, safety, and comfort 2, 8. For medical settings or when precise temperature measurement is critical, rectal thermometry remains the gold standard 1. Temporal artery thermometers provide a convenient alternative but should not be solely relied upon for fever detection in young infants 5.