The cervical mucus method is a type of natural family planning. Also called the Billings Ovulation Method, the cervical mucus method is based on careful observation of mucus patterns during your menstrual cycle.

Before ovulation, cervical secretions change — creating an environment that helps sperm travel through the cervix, uterus and fallopian tubes to the egg. By recognizing changes in your cervical mucus, you can try to pinpoint when you're likely to ovulate — and when you're most likely to conceive.

If you're hoping to get pregnant, you can use the cervical mucus method to determine the best days to have sex. If you want to avoid pregnancy, the cervical mucus method can help you figure out which days to avoid unprotected sex.

Using the cervical mucus 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.

The cervical mucus method is a way to identify fertile times to help you gauge the best days to have or avoid unprotected sex. Tracking your cervical mucus for either fertility or contraception is inexpensive and doesn't have any side effects. Some women choose to use the cervical mucus method for religious reasons.

The cervical mucus method is sometimes combined with another fertility awareness method, such as tracking basal body temperature. You might also use an electronic fertility monitor to measure hormone levels in your urine, which can tell you which days you're fertile. This combination of approaches is sometimes referred to as the symptothermal or symptohormonal method.

Using the cervical mucus method to promote fertility doesn't pose any risks.

Likewise, using the cervical mucus method for birth control doesn't pose any direct risks, but it doesn't offer protection from sexually transmitted infections. In addition, the risk of unintended pregnancy with the cervical mucus method is somewhat higher than with other methods of birth control.

It's estimated that as many as 23 out of 100 women practicing the cervical mucus method for birth control will get pregnant in the first year of typical use. With perfect use, the pregnancy rate may be as low as 3 out of 100 women a year.

Formal training is usually needed to master the cervical mucus method. You'll also need to make sure you check cervical secretions every day and keep track of changes. In addition, abstinence — or use of another type of contraception — is typically needed for 14 to 17 days each cycle.

To use the cervical mucus method, it's important to understand how cervical secretions change during a typical menstrual cycle. Generally, you'll have:

• No noticeable cervical secretions for three to four days after your period ends
• Scanty, cloudy and sticky secretions for the next three to five days
• Abundant, clear and wet secretions for the next three to four days — the period before and during ovulation
• No noticeable cervical secretions for 11 to 14 days until your next period begins

Although the specific length of these phases may vary, contact your health care provider if your cervical secretions don't follow this general pattern. You may have an infection that requires medical attention.

If you want to use the cervical mucus method for birth control, consult your health care provider first if:

• You recently had your first period, gave birth, or stopped taking birth control pills or other hormonal contraceptives
• You're breastfeeding
• You're approaching menopause
• You have a condition that disrupts regular ovulation, such as polycystic ovary syndrome

Your health care provider may discourage use of the cervical mucus method if you have persistent reproductive tract infections.

You can use the cervical mucus method no matter how many days long your menstrual cycles are. To use this method:

• Record your cervical secretions for several cycles. Starting the day after your menstrual bleeding stops, observe and record your cervical secretions on a daily chart — either on paper or with an app designed to track fertility signs.

  To avoid confusing cervical secretions with semen or normal sexual lubrication, avoid sex or use a barrier method of contraception during your first cycle. Also avoid douching, which can wash out cervical secretions and make it difficult to notice changes.

• Check your cervical secretions before and after urinating. Wipe — front to back — with toilet tissue. Record the color (yellow, white, clear or cloudy), consistency (thick, sticky or stretchy) and feel (dry, wet or slippery) of your secretions. Also note sensations of dryness, moistness or wetness in your vulva.

• Plan sex carefully during fertile days. You're most fertile when your cervical secretions are abundant, clear, stretchy, wet and slippery — much like a raw egg white. If you're hoping to get pregnant, this is the time to have sex. Ovulation most likely occurs during or one day after your last day of this type of cervical secretion — known as your peak day.

  If you're hoping to avoid pregnancy, unprotected sex is off-limits from the day your cervical secretions begin until four days after your peak day. If you have sex before your cervical secretions begin, you may want to avoid sex the next day and night so that you don't confuse semen and arousal fluids with cervical secretions.

  Some health care providers also recommend avoiding unprotected sex or using a barrier method of contraception during your period because it's difficult to detect cervical secretions when they're mixed with menstrual blood.

Interpreting and charting cervical secretions can be challenging. Most women need more than one instructional session to recognize the pattern of secretions in a typical menstrual cycle. Talk with your health care provider if you have questions or concerns.

A simpler version of the cervical mucus method is an approach called the TwoDay Method. With the TwoDay Method, you note whether you've seen cervical secretions that are clear, stretchy, wet and slippery — a sign of peak fertility — either today or yesterday. If the answer is "yes," then consider yourself fertile. Abstain or use a barrier method of birth control to avoid unintended pregnancy.