From the Research
For accurately measuring a newborn's fever at home, a digital rectal thermometer is the most recommended and accurate option, as supported by the most recent study 1. These thermometers provide the most precise core body temperature reading for infants under 3 months old. When using a rectal thermometer, apply a small amount of petroleum jelly to the tip, gently insert it about ½ inch into the rectum while holding your baby securely, and wait until it beeps (usually 10-30 seconds). Some studies suggest that temporal artery (forehead) thermometers can be used as an alternative, but they may not be as accurate as rectal thermometers, especially in critically ill neonates 1. Axillary (armpit) thermometers are another option but are less accurate than rectal readings. It's worth noting that ear thermometers were found to be equivalent to rectal thermometers in infants <6 months in a recent study 2, but this may not be the case for all ear thermometers, and more research is needed to confirm this finding. Avoid using oral thermometers for babies. When checking for fever, remember that a rectal temperature of 100.4°F (38°C) or higher indicates a fever in a newborn and requires immediate medical attention, as fevers in babies under 3 months can be serious.
The available evidence suggests that rectal thermometers are the most accurate method for measuring temperature in newborns, with some studies suggesting that temporal artery thermometers may be used as an alternative in certain situations. However, the most recent study 1 found that temporal artery thermometers are not accurate enough for critically ill neonates, and therefore, rectal thermometers remain the gold standard. Key points to consider when choosing a thermometer for a newborn include:
- Accuracy: Rectal thermometers are the most accurate method for measuring temperature in newborns.
- Ease of use: Temporal artery thermometers are less invasive and may be easier to use than rectal thermometers.
- Safety: Avoid using oral thermometers for babies, and be cautious when using ear thermometers, as their accuracy may vary.
In terms of specific thermometer types, the following options are available:
- Digital rectal thermometers: These are the most accurate method for measuring temperature in newborns.
- Temporal artery thermometers: These may be used as an alternative to rectal thermometers in certain situations, but their accuracy may vary.
- Axillary thermometers: These are less accurate than rectal thermometers and may not be suitable for newborns.
- Ear thermometers: These may be equivalent to rectal thermometers in infants <6 months, but more research is needed to confirm this finding.