Why are rectal temperatures not recommended in the newborn?

A) They are inaccurate.
B) They do not reflect core body temperature.
C) They can cause perforation of rectal mucosa.
D) They take too long to obtain an accurate reading.

Rectal temperatures are avoided in the newborn. If done incorrectly, the insertion of a thermometer into the rectum can perforate the mucosa. Rectal temperatures, if taken correctly, are considered an accurate reflection of core body temperature. The inherent risks and intrusive nature limit the use. The time it takes to determine body temperature is related to the equipment used, not the route only.