“Fertility awareness” means that a woman knows how to tell when the fertile time of her menstrual cycle starts and ends. (The fertile time is when she can become pregnant.)

Sometimes called periodic abstinence or natural family planning.

A woman can use several ways, alone or in combination, to tell when her fertile time begins and ends.

Calendar-based methods involve keeping track of days of the menstrual cycle to identify the start and end of the fertile time.

– Examples: Standard Days Method and calendar rhythm method.

Symptoms-based methods depend on observing signs of fertility.

– Cervical secretions: When a woman sees or feels cervical secretions, she may be fertile. She may feel just a little vaginal wetness.

– Basal body temperature (BBT): A woman’s resting body temperature goes up slightly after the release of an egg (ovulation), when she could become pregnant. Her temperature stays higher until the beginning of her next monthly bleeding.

– Examples: TwoDay Method, BBT method, ovulation method (also known as Billings method or cervical mucus method), and the symptothermal method.

Work primarily by helping a woman know when she could become pregnant. The couple prevents pregnancy by avoiding unprotected vaginal sex during these fertile days—usually by abstaining or by using condoms or a diaphragm. Some couples use spermicides or withdrawal, but these are among the least effective methods.

Effectiveness depends on the user: Risk of pregnancy is greatest when couples have sex on the fertile days without using another method.

As commonly used, in the first year about 25 pregnancies per 100 women using periodic abstinence. (How these women identified their fertile time is not known. Pregnancy rates for most of the specific fertility awareness methods as commonly used are not available.) This means that 75 of every 100 women relying on periodic abstinence will not become pregnant. Some newer fertility awareness methods may be easier to use and, thus, more effective (see Question 3).

Pregnancy rates with consistent and correct use vary for different types of fertility awareness methods (see table, below).

In general, abstaining during fertile times is more effective than using another method during fertile times.

Pregnancy Rates With Consistent and Correct Use and Abstinence on Fertile Days

Return of fertility after fertility awareness methods are stopped: no delay

Protection against sexually transmitted infections (STIs): none

None

Known Health Benefits

Help protect against:

Risks of pregnancy

Known Health Risks

none

Why Some Women Say They Like Fertility Awareness Methods

• Have no side effects
• Do not require procedures and usually do not require supplies
• Help women learn about their bodies and fertility
• Allow some couples to adhere to their religious or cultural norms about contraception
• Can be used to identify fertile days by both women who want to become pregnant and women who want to avoid pregnancy

Fertility awareness methods:

• Can be very effective if used consistently and correctly.
• Do not require literacy or advanced education.
• Do not harm men who abstain from sex.
• Do not work when a couple is mistaken about when the fertile time occurs, such as thinking it occurs during monthly bleeding.

Women who are infected with HIV, have AIDS, or are on antiretroviral (ARV) therapy can safely use fertility awareness methods.

Urge these women to use condoms along with fertility awareness methods. Used consistently and correctly, condoms help prevent transmission of HIV and other STIs. Condoms also provide extra contraceptive protection for women on ARV therapy.

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