What are Fertility Awareness Methods?

Fertility Awareness Methods (FAM) (sometimes called natural family planning) are practices that help someone determine when they are most likely to get pregnant (the fertile window) so that they can either avoid sexual activity or use barrier methods during that time to avoid pregnancy.

FAM may predict the fertile window by using a calendar or counting days from previous menstrual periods; or identify the fertile window by observing symptoms and signs of ovulation; or use a combo of both approaches.

There are a number of different methods that fall under the category of Fertility Awareness Methods:

  • Calendar Method and variations such as the Standard Days Method
  • Cervical Mucous Method
  • Basal Body Temperature Method
  • Symptothermal Method
  • Digital apps such as Natural Cycles that use the calendar method and something additional such as basal body temperature (Please note: most period tracking apps aren’t appropriate for pregnancy prevention)
  • Fertility Monitors

How does FAM work? 

FAM is a way to predict high and low fertile times in your cycle. It is based on body signs, which change during each menstrual cycle in response to the hormones that cause ovulation (the release of an egg). The most common ways of monitoring ovulation that are used in FAM are tracking past periods, changes in cervical fluid and checking and charting basal body temperature (your body temperature when you wake up in the morning, after at least 6 hours of uninterrupted sleep).

If you use FAM and don’t want to get pregnant, you must use a barrier method birth control (such as condoms or cervical caps) or not have sex during the times when you are more likely to get pregnant.

FAM relies on the following:

  • An egg is usually released once each menstrual cycle
  • The egg lives 12 to 24 hours
  • Sperm can live up to 6 days in the uterus, and be able to fertilize an egg during this time.
  • This means that a person could get pregnant as long as 6 days before ovulation and 2 -3  days after ovulation, a total of 8-9 days in each menstrual cycle

How effective is FAM? 

Because FAM may include different methods and are dependent on many factors (such as the length of a person’s cycle and what birth control is used during their fertile times) it is difficult to say how effective they will be for an individual. Overall, they are approximately 76% effective in actual use, meaning that 24 people out of 100 would get pregnant using FAM methods as their only form of birth control for one year. FAM is only as effective as the birth control used during fertile times. The most effective way to use FAM is to abstain from vaginal intercourse during the fertile window.

People ovulate at different times in their cycle and that can change from month to month, so knowing when your past periods happened or tracking them on a phone app is not a very accurate way of knowing when you can get pregnant. It is a myth that people always ovulate 14 days after the first day of their period and it is possible to get pregnant from sex during or right after a period.

  • Free to low cost
  • No medical side effects
  • May develop greater communication, cooperation, and responsibility for partners.
  • May help track and improve awareness of PMS symptoms
  • Can help someone learn about their body
  • May encourage different kinds of sexual exploration and expression other than intercourse during the fertile window
  • Can also be used to figure out when someone is fertile if they are trying to get pregnant.
  • High failure rate
  • Requires commitment from both partners
  • Decreases spontaneous intercourse
  • People report difficulty with abstinence during the fertile window
  • Does not protect against Sexually Transmitted Infections (STIs)
  • Effectiveness can be impacted by circumstances such as irregular periods; sleep issues or illness; changes in discharge (due to arousal, semen, infections, etc.); changes in ovulation patterns due to things like aging or stress; and so on.
  • Can require a lot of work and time
  • Can’t be relied on immediately – most methods require several months of use before relying on it
  • Might not be suitable at certain times such as for people who have recently given birth or are approaching menopause

What if sex happens at a time I might be fertile?

Consider using Emergency Contraception to lower the chances of pregnancy. For more information please see our website at You may also want to consider a more effective method of birth control for future pregnancy prevention. Using the Emergency Contraceptive Pill (ECP) can affect your cycle and when you ovulate for up to 2 months after taking it, making it difficult to accurately predict fertile times following ECP use.

Questions? We’re here for you!

We know it can be confusing to choose a method. We are here to help.
You can visit one of our Options for Sexual Health Clinics to speak with a health care provider. Our Sex Sense Team is available Monday-Friday 9 a.m. to 9 p.m. by phone 1-800-739-7367 or by email at to answer your questions about birth control, or any other questions about sex, sexuality, or sexual health. This fact sheet contains general information and should not be used in place of individual consultation with a qualified healthcare provider.

Have a question about sexual health?