What is a Basal Body Temperature Chart?

A basal body temperature chart helps a woman keep track of her most fertile times. It is typically used to help a woman who is trying to become pregnant. However, it may also be used by a woman who is trying to prevent pregnancy, as it is a tool for monitoring fertility. Unfortunately, it is less effective than most contraceptive methods, so its optimal use is for those who want a baby.

A basal body temperature chart requires a woman to take her temperature every day of her cycle, beginning with the first day of her menstrual period. To do this, she'll use a special basal body thermometer to take her temperature immediately upon waking up in the morning; this should be done at the same time every day or as close to it as possible. It should be done before eating, before going to the bathroom and before engaging in any other activity that might alter her temperature. This number is then recorded on the basal body temperature chart.

Once a woman takes her morning temperature, she plots it on her basal body temperature chart. If she is also keeping track of her cervical mucus, another important part of detecting fertility, she will then go to the bathroom and use a finger or toilet paper to check the consistency of her cervical mucus, recording it on the chart. A woman's cervical mucus may appear clear and stretchy around the time she ovulates.

At some point in keeping her basal body temperature chart, a woman may notice that her temperature has spiked; though this rise in temperature may be very slight, it indicates that she has ovulated. Some women, though not all, also note a drop in temperature right before they ovulate. By keeping track of changes in waking temperature and cervical mucus on a basal body temperature chart, a woman can do a credible job of pinpointing fertility times. With this information at hand, she can choose to have sexual intercourse at the time she is most fertile: in the days before ovulation and on the day she ovulates. When charting works well, it helps a woman to become pregnant.