BASAL BODY TEMPERATURE

The purpose of charting your basal body temperature is to determine when ovulation occurs. Charting is useful for couples who are trying to get pregnant, trying to avoid pregnancy, or for any woman who simply wants a better understanding of her body. The basal body temperature is most easily measured with a special thermometer which has a range of only a few degrees, known as a basal thermometer. This thermometer can be found at most large drug stores and costs about $6. It can be used orally, vaginally, or rectally, but should be used in the same location each time. Take the basal temperature upon waking, before doing any activity, and keep in place for a full five minutes. Don't fall asleep with the thermometer in your mouth! You could break it and swallow the mercury. If this happens, call your doctor at once! You might consider a digital basal thermometer, which is safer, faster, and just as accurate.

USING THIS CHART

Day one on the chart below refers to the first day of bleeding in a woman's monthly cycle. The blank boxes beneath are to write in the day of the month. During menstruation a woman will write H, M, or S in the row labeled "Bleeding" for as long as menstruation persists. Any mid-cycle spotting can be indicated in this row as well. On the fifth day, temperature taking should begin. The temperature should be recorded on the corresponding line every morning until the next period starts. Connect each dot with a line. A new chart must be used at the onset of a new period.

To successfully utilize the sympto-thermal method of birth control, you will need to chart your basal temperature and in additional other body signs. By simply filling in the appropriate boxes, a woman can record the presence of cramps, spotting, headaches, breast tenderness, and overall mood. Boxes are also provided for tracking changes in the cervix, including cervical mucus characteristics, the size of the cervical opening, how high the cervix is in the vagina, and the firmness of the cervix.

INTERPRETING THIS CHART

Ovulation will occur around the time of temperature shift. Before ovulation, the temperature is likely to be between 97.2 and 97.4 degrees F. After ovulation, it will rise by at least 0.5 degrees and is usually above 98 degrees F. When the temperature stays elevated for at least three days, a woman may assume she has already ovulated. Intercourse for the rest of the cycle will not result in pregnancy. A number of additional body signs should correlate with ovulation, including the presence of a clear, stretchy cervical mucus, a soft, open cervix, and sometimes mild cramping or even spotting. Take a look at the sample chart below. Can you tell when ovulation occurred?

Download Chart: GIF/On-Screen Version

The information presented here is simply an overview of the process. Before using Natural Family Planning as birth control it is recommended that you take a class with an experienced instructor. The books and websites listed below include reference materials and organizations which offer nationwide classes.