Basal body temperature and cervical mucus

If you're trying to get pregnant— or, if you're trying not to— it's helpful to know when you're ovulating so you can time intercourse accordingly. Many women have had success using ovulation predictor kits, which are handy because they tip you off before you ovulate. But the natural way to get a sense of your ovulation cycle is to chart your basal body temperature (BBT) and monitor your cervical mucus.

What is basal body temperature?
Basal body temperature (BBT) is your temperature when you first wake up in the morning. Before you even get out of bed to brush your teeth or start your day, pop a basal thermometer (available at drugstores) into your mouth. (It's important to try to wake up and take this reading at about the same time each morning.) This thermometer shows the minute incremental degree changes that a regular one can't. Most basal thermometers come with a temperature plotting chart. (For instructions on how to fill one in and a sample you can download, click here.) Make some extra copies of the chart in case it takes you a few months to get pregnant.

Your BBT probably ranges from 97.2 to about 97.7 degrees before ovulation. During the two or three days after you ovulate, hormonal changes have caused a rise in your BBT of between 0.5 and 1.6 degrees, which lasts at least until your next period. You'll probably notice your temperature spiking on other days, but unless it stays that way, you probably haven't yet ovulated. If you become pregnant, your temperature will stay elevated throughout your pregnancy.

It's helpful to chart your temperature for a few months so you can see whether there's a pattern to your cycle. If you're sick or fail to take your temperature immediately upon awakening, any pattern you find may be inaccurate.

What is cervical mucus?
There are many different types of vaginal discharge, one of which is cervical mucus. The type of mucus your body produces provides clues to your fertility. You can check your cervical mucus using either your fingers or toilet paper. On days when you're not fertile, the mucus from your cervix is either light or sticky (about the same texture as sticky rice). During the few days leading up to ovulation, when you're most fertile, you'll have more discharge — clear and slippery with the consistency of raw egg white. You are most fertile on the last day you notice cervical mucus of this kind. It usually happens either the day before, or the day of, ovulation. The change in volume and texture of your cervical mucus is due to the increase in estrogen levels that accompanies ovulation.

Which one should I chart?
Both, say many fertility experts. A combined approach will give you the clearest picture of your cycle, so you can more accurately predict ovulation