A temperature chart is a tool that many women use when attempting to conceive, according to WebMD. By tracking basal body temperature over the course of a few menstrual cycles, women can identify a pattern in the minute changes in basal body temperature that indicate that ovulation has occurred.
After ovulation, a woman's body produces progesterone, which causes the body's temperature to rise slightly, explains WebMD. The body sustains this 0.1 to 0.2 degree Fahrenheit temperature elevation until progesterone levels drop and the next cycle begins. If pregnancy occurs, the body maintains progesterone production and the elevated body temperature.
To collect the necessary data for the temperature chart, a woman takes a temperature reading every day upon waking and before any activity, including getting out of bed, notes WebMD. She records these data points and creates a graph tracking daily temperature readings. This allows her to visualize any patterns in the length of her cycle and the day of her cycle on which the temperature increase occurs. This knowledge aids in predicting when ovulation occurs and allows for increased sexual activity in the days before ovulation, which increases the probability of pregnancy.
Because ovulation timing and women's menstrual cycles can be irregular, basal body temperature charts are not always an effective tool, reports WebMD. Medical professionals serving women trying to conceive can assist in identifying patterns in the temperature data and evaluating outlying data points.