Charting Your Fertility Cycle
Tips for Taking and Understanding Your BBT
- Begin taking your temperature on the first day of your period. (You will need a thermometer that measures by tenths of degrees.)
- Take it at about the same time every day, preferably before you get out of bed in the morning.
- Don't do anything -- eat, drink, smoke, or even move around -- before you take your temperature.
- You can take your temperature however you want -- orally, rectally, or vaginally -- but make sure you use the same technique each time.
- Write down your temperature every day on your fertility chart; you can make a graph with each day of your cycle on the bottom and temperatures on the left, connecting the dots as you go.
- Keep in mind that you will probably get some occasional freak readings -- either high or low temperatures -- that don't fit into the larger pattern. If they don't happen often, don't worry about them.
- After few months you may begin to see a pattern indicating the usual timing of your ovulation. You may want to have your doctor look at your chart to help you interpret it.
- Although BBT charting is a widely used technique, it is by no means foolproof. Some women may not see a clear pattern emerge by recording their temperature. Since ovulation can occur at different times in your cycle from one month to the next, your BBT chart may not be effective at predicting when you'll ovulate.
Cervical Mucus and Ovulation
Although it may take some detective work -- and may be a little off-putting to some -- learning to detect changes in your cervical mucus is an easy and highly effective of way of predicting ovulation. According to a recent study, it's a more accurate way of predicting ovulation than BBT, although it can be used in conjunction with it.
The mucus released by the cervix serves different purposes. When you're not ovulating or approaching ovulation, cervical mucus prevents sperm from getting into the uterus at a time when you couldn't become pregnant anyway. As you near ovulation, your cervix secretes an increasing amount of mucus, and when you are most fertile, your cervical mucus is stretchy and clear, like the consistency of egg whites. At this point, the mucus actually protects the sperm and helps it in its journey toward the egg.