For women who are unsure of when they ovulate, keeping a basal body temperature chart for several months may help to identify the time of ovulation. Charting involves taking one's temperature every morning upon waking up and recording the results. For optimal accuracy, this must be performed before the woman drinks a cup of hot coffee or brushes her teeth, as these events can interfere with the temperature reading.
When the temperature goes up 0.5 degrees, the woman is in the process of ovulating. This is not recommended as a method to plan intercourse, as the rise in temperature is caused by an increase in progesterone after the follicle's release of the egg and the window of opportunity for conception may be missed by the time the temperature rises.
Unfortunately, BBT charting is time consuming, frustrating, and is a daily reminder to the patient that she is having difficulty conceiving. Though it is a reasonable first step to attempting conception, if the results are inconclusive after three months, it is recommended that the couple move on to other methods to detect ovulation such as urinary LH detection kits.
Basal body temperature charts also provide useful information as to the length of the second half of your menstrual cycle (luteal phase). This information can be useful, especially in order to detect a shortened luteal phase, which may interfere with normal pregnancy implantation and growth.