What is basal body temperature?
Basal body temperature (or BBT) is the temperature of the body at rest. The BBT method requires charting your basal - think 'base' - body temperature when you're completely at rest. For most women, 96 to 98 degrees is considered normal prior to ovulation and 97 to 99 degrees after ovulation. By charting the differences - in one-tenth degree increments - you can determine when ovulation has taken place.
BBT Charting - How Can It Help In Conceiving?
During the first two weeks of a woman's cycle, her body temperature is lower (97.0 to 97.5 F), due to the presence of estrogen. With ovulation, a rise in body temperature takes place - caused by an increase of the hormone progesterone - in order to provide a warmer, more fertile environment in the womb. A minimum temperature rise of 0.4 to 0.6 degrees F can be measured - and this change will last through the duration of the menstrual cycle. By monitoring when this temperature change takes place, you can estimate when ovulation has taken place.
How to take your Basal Body Temperature?
1. Taking Your BBT Temperature
Take your BBT temperature first thing each morning - as soon as you wake up. It is recommended that you remain in bed (as any physical activity can increase your resting temperature), as well as avoid eating or drinking. Coffee can wait! Either insert the thermometer in your mouth - or alternatively your rectum - and wait five minutes. Read the temperature to within 1/10 of a degree and record the reading.
2. Charting Your BBT Temperature
Starting on day one of your menstrual cycle - the first day of your period - begin recording your BBT temperature using a calendar or notebook and graph paper. Each morning, record your temperature. Plot each day's BBT on the graph. Your temperature rise may be sudden, gradual, or in steps. The pattern may vary from cycle to cycle.
3. Predicting Ovulation
For most women, 96 to 98 degrees is considered normal prior to ovulation and 97 to 99 degrees after ovulation. By charting the differences - in one-tenth degree increments - you can determine when ovulation has taken place. Typically a rise of at least 0.4 to 0.6 degrees will take place at ovulation, though for different women the temperature increases may be sudden or gradual.