The Normal Basal Body Temperature
The normal Basal Body Temperature or BBT is the lowest body temperature in a 24-hour period.
In women, it fluctuates with the phases of the menstrual cycle and can
often be used as an important sign to predict the occurrence of
The Normal Value
No single value is normal for every woman. However, a range of 96 to
98°F(35.6 to 36.7°C) is considered normal before the ovulation phase and
97 to 99°F (36.1 to 37.2°C) after ovulation. Notice it is slightly
higher after ovulation following a normal cycle.
The Menstrual BBT Pattern
The process of ovulation and the hormone progesterone produce and
sustain a slight rise in the BBT during the luteal phase. That means as a
woman moves from the follicular phase into the luteal phase.
through ovulation, her basal body temperature slightly increases. When
she transitions from the luteal to the follicular phase, the BBT equally
The temperature change is usually about 0.5 to
1 degrees Fahrenheit(0.25 to 0.5 degrees Celsius. Notice that the
change is very small and you cannot reliable feel it. In fact a regular
thermometer is not very reliable to detect this change. A special
thermometer called the Basal thermometer is often required especially if
you want to do fertility charting.
Return To Menstruation Home