Some properties of rectum and vagina as sites for basal body temperature measurement.

The choice of site for body temperature measurement and consistency in positioning the thermometer are important in achieving reliable and interpretable basal body temperature graphs in women. The distribution of temperatures in vagina (TV) and rectum (TR) were measured in women upon awakening. There were no significant differences between TR and TV at insertion depths of 5, 9, or 13 cm. Estimation of deep body temperature was not improved by inserting a thermojunction beyond 5 cm in vagina or rectum. Rates of change in TV following ingestion of a 300-ml iced drink were significantly greater than rates of change in TR.