basal body temperature (during ovarian cycle)
Last reviewed 01/2018
The BBT is the temperature on awakening before any activity. A rise of 0.5 degrees centigrade in the last 14 days of the cycle indicates that ovulation has occurred. The rise is due to the effects of progesterone and should persist for about 11 days. However, BBT is an unreliable measure of the precise occurrence of ovulation and is not a reliable method of contraception.