Comparison of rectal, axillary, and inguinal temperatures in full-term newborn infants.

Rectal, axillary, and inguinal temperatures were compared in 120 full-term infants aged 12 to 48 hours. Thermometers were placed in randomized sequential order and temperatures were recorded every 30 seconds until the reading remained constant for 90 seconds (stabilization). At least 95% of subjects reached temperature stabilization at all sites by 5 1/2 minutes. Mean difference between axillary and inguinal readings was 0.6 degrees F; between rectal and inguinal readings, 0.8 degrees F; and between rectal and axillary 0.2 degrees F. Although the greatest difference between mean temperature readings was found between the rectal and inguinal sites (0.8 degrees F), this pair of readings also had the highest correlation. This finding indicates that inguinal site temperatures are more reflective of rectal temperatures and may be less sensitive to effects of brown adipose tissue heat generation.