How effective is the fertility awareness method for birth control?

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According to The American College of Obstetricians and Gynecologists (ACOG), when people use fertility awareness correctly, less than 1–5 people out of 100 will become pregnant in the first year of using the method.

Correct use of fertility awareness means people always use the method throughout their cycle consistently and exactly as the instructions state.

If people do not always use fertility awareness consistently or correctly, it can increase their risk of becoming pregnant.

In the first year, inconsistent and incorrect usage is typical of the average person using fertility awareness and means 12–24 people out of 100 will become pregnant.

There are different types of fertility awareness methods people can use to prevent pregnancy. People may want to choose a combination of methods.

The temperature method

This method uses the basal body temperature, which is the body’s resting temperature. People take their temperature first thing every morning before getting out of bed, eating, drinking, or doing anything else.

A person can do this with a digital oral thermometer or one specifically designed to measure basal body temperature.

In most people who menstruate, basal body temperature increases slightly from ovulation to the end of the menstrual cycle. In the 2–3 days before this increase, people are most fertile.

People track their daily temperatures on a chart to predict their most fertile days. People will need to avoid sex or use another form of birth control during their fertile days to prevent pregnancy.

The temperature method is not reliable on its own, and it may be better to combine it with the cervical mucus method. The combination of these methods is the symptothermal method.

The cervical mucus method

The cervical mucus method looks at changes in the mucus produced by the cervix. Cervical mucus increases just before ovulation, so it can indicate when a person is fertile.

People can check their cervical mucus by looking at the discharge in their underwear, wiping the opening of their vagina before using the toilet, or inserting a finger into their vagina.

People will need to check the color and texture of the mucus and record the details daily on a chart.

To prevent pregnancy, people will need to avoid sex or use other birth control when cervical mucus is present.

The standard days method

The standard days method uses a regular menstrual cycle to predict a person’s most fertile days.

For a cycle consistently between 26–32 days, people may be most fertile between days 8–19.

To prevent pregnancy, people should avoid sex or use other birth control during these days.

Advantages of fertility awareness can include:

• low cost
• not using medications or devices
• safe with no side effects
• hormone-free
• learning more about individual cycles and fertility patterns

The fertility awareness methods require a lot of self-discipline. They can help a person get to know their body better but some disadvantages can include:

• no protection against sexually transmitted infections (STIs)
• inconsistent or incorrect use may increase pregnancy rates
• people may need up to 3 months of tracking before relying on some methods
• requires daily tracking

Fertility awareness may be more difficult or unsuitable for some people, such as those who:

• bleed in between menstrual cycles
• are not able to avoid sex or use other birth control during fertile days
• have just started menstruating or are approaching menopause
• have recently given birth
• have recently stopped using hormonal birth control

Other birth control options include:

• Sterilization: Female tubal ligation or a male vasectomy are medical procedures that act as permanent birth control.
• Long-acting reversible contraceptives (LARC): These can last for years and include hormonal implants and intrauterine devices.
• Short-acting hormonal birth control: These include the birth control pill, patch, shot, or vaginal ring, and people will need to use these regularly, such as daily or monthly.
• Barrier methods: People use these every time they have sex and include condoms, diaphragms, the sponge, or a cervical cap.

This section answers some frequently asked questions about fertility awareness methods for birth control.

Is fertility awareness reliable?

The reliability of fertility awareness may depend on the methods people use and how correctly and consistently they use it.

The standard days method may only be effective for people with a regular menstrual cycle, meaning it is consistently between 26–32 days.

The temperature method is not reliable on its own and is more effective if people combine it with other fertility awareness methods.

The signs fertility awareness relies on depend on many different factors, such as:

• stress
• illness
• medications
• using feminine hygiene products
• sex
• chest or breastfeeding
• pelvic exams
• irregular menstrual cycles

What is the failure rate of fertility awareness?

According to a 2022 article, correct or perfect use of fertility awareness methods for 1 year may result in fewer than 5 in 100 people getting pregnant. For some methods, it may be less than 1 in 100.

For typical use for 1 year, the failure rate may vary between 2–23 per 100 people. Most research suggests typical use over 1 year may result in fewer than 15 in 100 people getting pregnant.

Fertility awareness is a method of birth control that tracks the menstrual cycle to show when a person is most fertile. To prevent pregnancy, people will need to avoid sex or use other birth control during their fertile days.

If people want to use fertility awareness, it may be best to learn from a healthcare professional or qualified teacher.