How to Use Natural Family Planning

Four Parts:Checking Your Cervical MucusCharting Your TemperatureUnderstanding How Natural Family Planning (NFP) WorksWhen Should You Try This?

If you're like most people, you probably have a fuzzy idea of something called Natural Family Planning (NFP). You may know that a calendar and taking your temperature are somehow involved, but you're unsure of how the method actually works. NFP determines what phases of your menstrual cycle are fertile and infertile periods. For the method to be effective, you'll need to become aware of the daily changes in your body throughout every menstrual cycle. This way, you can use NFP to plan a pregnancy, prevent a pregnancy (without needing to use hormones, condoms, or intrauterine devices), or just understand what's going on with your monthly cycle.[1]

See When Should You Try This? to learn more about when using natural family planning might be a good course of action to consider. Keep in mind that average use shows a failure rate of approximately 25%, while correct and consistent use shows a failure rate of approximately 10%.[2]

Part 1
Checking Your Cervical Mucus

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    Distinguish between fertile and infertile cervical mucus. During the menstrual cycle, your cervix creates mucus that changes to reflect your fertility. After your period, you'll notice several dry days where little or no mucus is produced (possibly making sex feel a little uncomfortable). This is an infertile time. But, the mucus will gradually become tacky, cloudy, and then wetter, stretchier, and slippery (looking like raw egg white) over the course of several days. This wet, stretchy, and slippery mucus signals a fertile phase that usually lasts around four days.
    • While you're menstruating, this mucus is obscured by the menstrual flow.
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    Check your cervical mucus every day. Before using the toilet, take a clean tissue and wipe your vagina. If there's any mucus on the tissue (or in your underwear), pay attention to the color and consistency. Wash your hands and insert your index finger into your vagina. Notice the color. To check the consistency, gently rub a bit of the mucus between your index finger and thumb before separating your fingers. Check your mucus two to three times a day.[3] The following characteristics of cervical mucus can mean that you're:[4]
    • Fertile: Mucus is creamy, lotiony, stretchy, slippery, similar to egg whites
    • Infertile: Mucus is dry, sticky, crumbly, or gummy
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    Track your cervical mucus on a calendar. Since you're checking your cervical mucus two to three times a day, you only need to write down the most fertile or wet mucus you experienced during the day. You may be surprised to find that your mucus can change:[5]
    • Throughout the day
    • Based on how long your cycle is
    • In amount
    • If you use feminine "hygiene" products
    • If you use hormonal contraception or spermicides
    • If you have a vaginal infection
    • If you're sexually aroused
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    Determine where you're at in your menstrual cycle. By charting your cervical mucus, you can look at the calendar and notice trends in your fertility. For example, you may see that you had five dry days after your period, followed by two sticky days, then a lotiony day, and a slippery day (indicating ovulation). This shows increasing fertility following menstruation.
    • If you're trying to prevent pregnancy and you notice your cervical mucus is starting to become wetter or stretchier, take extra precautions. You can either abstain from sex during this increasingly fertile phase or use additional contraceptives.
    • If you're trying to become pregnant, you'll want to start timing sex around the more fertile phases of your cycle (when you notice wet, stretchy, clear mucus and most importantly around ovulation).[6]

Part 2
Charting Your Temperature

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    Prepare to take your temperature. You'll need the same calendar that you've been using to chart your cervical mucus. While you can use any digital thermometer to take your daily temperature, it's best to use a Basal body thermometer which will give you the highest degree of accuracy. You'll be taking your temperature orally, although rectal temperatures are the most accurate.[7]
    • During your menstrual cycle, your body temperature changes subtly. You should be able to see the temperatures rise by about a degree following ovulation. They'll stay slightly higher until you start menstruating or they'll stay elevated (which can indicate pregnancy).
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    Take your temperature every morning. You should take your temperature every morning before getting out of bed, eating, drinking, or using the bathroom. Take your temperature at the same time every morning. If you like, you can set an alarm, take your temperature, and go back to bed. Record your daily temperature on your charting calendar.[8]
    • You can also chart your temperature and cervical mucus on graphs that you can get from your doctor, a woman's health center, and most pharmacies. This will make it easier to see temperature shifts and confirm ovulation.
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    Make a coverline on your chart or graph. Once you've been charting your temperatures for a while, you should notice that your body temperature usually stays around a certain temperature. You'll need to look for a temperature that is at least 0.2 degrees higher than the previous six days. Of those six days, look for the highest temperature. Draw a horizontal line that is 0.1 degree higher than that temperature to make your coverline.[9]
    • The coverline is simply an easy visual way to glance at your chart and see if you've ovulated and if your temperatures remain high (possibly due to pregnancy).
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    Use your temperatures to understand fertility. Unlike cervical mucus, you won't be able to use your daily temperature to determine if you're fertile or not. This is because a noticeable temperature shift will happen after changes in fertility have already taken place. While this can be helpful in confirming that ovulation occurred, it makes it almost impossible to rely on temperature changes alone to prevent pregnancy.[10] Other things can also impact your daily temperature. These include:[11]
    • Drinking alcohol the night before
    • Taking your temperature at a different time
    • Having a fever
    • Being sick
    • Stress
    • Difficulty sleeping
    • Medications
    • Changes in time zones

Part 3
Understanding How Natural Family Planning (NFP) Works

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    Learn how your menstrual cycle affects fertility. The average menstrual cycle lasts 28 days and starts on the first day of menstruation or bleeding. After menstruation ends, your body prepares to ovulate, or release an egg for potential fertilization and pregnancy. Ovulation, the peak of fertility in your cycle, usually happens around day 14 of the cycle. Because of this, the three to four days before ovulation are increasingly fertile, but fertility drops off following ovulation.[12]
    • If no egg is fertilized by sperm following ovulation, your body will enter an infertile phase, followed by menstruation, and the cycle repeats.
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    Prepare to watch for fertility signs. While you can keep track of the basics of your menstrual cycle (when your period starts and ends) on a calendar, you'll need to pay attention to physical symptoms of fertility. Cervical mucus is one of the best indicators of your fertility. Since your fertility is different from day to day, monitoring your cervical mucus every day will give you a more accurate indicator of fertility than if you were only tracking dates on the calendar. You'll also need a basal body thermometer to take your temperature every morning.
    • The basal body thermometer gives a more detailed temperature reading, usually to the 1/100th of a degree.[13] You'll be tracking your temperature to confirm if you have ovulated.
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    Decide if Natural Family Planning is right for you. You'll need to consider why you want to use NFP (planning or preventing a pregnancy). If trying to prevent a pregnancy using NFP, you'll need to be disciplined enough to take and chart your cervical mucus and temperature every day. You'll also have to follow the rules concerning sexual abstinence during fertile periods (or use backup contraception). If trying to become pregnant, NFP can be a great way to understand what's happening in your menstrual cycle, making it easier to time sex around your most fertile times.[14]
    • Since NFP doesn't protect against Sexually Transmitted Infections (STIs), you may still want to use a condom, especially if you're not in a monogamous relationship.

Part 4
When Should You Try This?

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    Consider NFP when you can regulate your menstrual cycle. While it is possible to use natural family planning when you have an irregular menstrual cycle, the practice will be more difficult under those circumstances. Natural family planning is easiest for women with regular, easily tracked cycles.[15]
    • If you have an irregular cycle, consider talking with your OB/GYN for additional assistance in tracking your cycles before attempting NFP. Your OB/GYN can also review other family planning options with you.
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    Approach NFP with serious dedication. While natural family planning can be highly effective when followed correctly, it also requires considerable dedication. You'll need to track the changes to your bodily consistently. Additionally, you also need to be willing to abstain from sex during your fertile periods.[16]
    • Since NFP can also help you become pregnant when you're ready to start a family, it can also be a good practice to use for these purposes. You'll still need to remain dedicated to charting your changes, but there's little to no risk involved when intending to get pregnant using NFP.
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    Try NFP for stable, monogamous relationships. Natural family planning does not protect against STIs, so if you plan on having multiple sexual partners, it would be safest to use condoms instead of or in conjunction with NFP.[17]
    • Additionally, errors in calculation or lax record-keeping can increase your risk of an accidental pregnancy while using NFP. An unplanned pregnancy can be more difficult to handle when you are not in a long-term, stable relationship.
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    Attempt NFP when you don't need any guarantees. Since errors in charting can reduce the effectiveness of NFP and may result in unplanned pregnancies, it's best to try NFP if you're financially, emotionally, and physically able to handle becoming pregnant, even when becoming pregnant is not your desired outcome.[18]
    • One positive of NFP is that it costs little to no money to use since you won't have to worry about prescriptions, devices, or extra visits to the doctor. That said, if you aren't able to remain consistent in your use of NFP, an unplanned pregnancy may cost you more in the long run than using standard forms of contraception would.
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    Use NFP to address religious concerns. Some faith traditions hold a negative view of many or all forms of contraception, but in most cases, these faiths are open to the practice of natural family planning.[19] Instead of artificially limiting or preventing the inherent gift of fertility, natural family planning allows you to honor and work with your fertility while planning your family.
    • Natural family planning allows both spouses to give to each other fully, without holding anything back from one another.[20]
    • Note, however, that the same faith traditions that view contraception negatively typically hold a negative view of extramarital sex, as well. If considering NFP for religious reasons, you should also take the status of your relationship into consideration.


  • Natural Family Planning isn't foolproof since it's open to human error. It's accuracy is determined by your discipline and adherence to the method's rules.
  • The failure rate of natural family planning is about 25%.[21]
  • When using the temperature method your body temperature can be altered by illness or other factors, which can affect accuracy.

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Categories: Birth Control and Contraceptives | Faith and Belief