Basal body temperature can be used to predict fertility to help you gauge the best days to have or to avoid unprotected sex. Tracking your basal body temperature for either fertility or contraception is inexpensive and doesn't have any side effects. Some women choose to use the basal body temperature method for religious reasons.

The basal body temperature method can also be used to detect pregnancy. Following ovulation, a rise in basal body temperature that lasts for 18 or more days may be an early indicator of pregnancy.

The basal body temperature method may be combined with another method of natural family planning, such as the cervical mucus method. This combination is sometimes referred to as the symptothermal method.

Nov. 18, 2011