Using the basal body temperature method to promote fertility doesn't pose any risks.

Likewise, using the basal body temperature method for birth control doesn't pose any direct risks, but it doesn't offer protection from sexually transmitted infections. In addition, it's one of the least effective natural family planning methods. An estimated 25 out of 100 women who use basal body temperature plus another fertility awareness-based method, such as the cervical mucus method, will get pregnant in the first year of typical use.

Using the basal body temperature method for birth control requires motivation and diligence. If you don't want to conceive, you and your partner must avoid having sex or use a barrier method of contraception during your fertile days each month.

Keep in mind that your basal body temperature can be influenced by many factors, including:

  • Illness
  • Stress
  • Shift work
  • Interrupted sleep cycles or oversleeping
  • Drinking alcohol
  • Travel and time zone differences
  • Gynecologic disorders
  • Certain medications

Some women also ovulate without a clear rise in basal body temperature.

Nov. 18, 2011