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revised Wednesday April 22 2009
healthy sexuality
Birth Control Methods

Natural Family Planning

Natural Family Planning (NFP) is a general term for methods a woman can use to determine her fertile days of the month.

NFP prevents pregnancy by not having unprotected intercourse during a woman’s fertile days.

How to Use Natural Family Planning

You can use the Calendar Tracking Method; Basal Body Temperature (BBT); and Cervical Mucus methods together or separately to determine when you’re the most fertile. Once you know your body's fertile period, you can either abstain from sexual intercourse or use one of the barrier methods during that time.

Get To Know Your Menstrual Cycle

The first step to charting your fertility is getting to know your monthly cycle.

There are two parts to your menstrual cycle: before and after ovulation. The average menstrual cycle is 28 days.

Menstrual Cycle

Day 1

  • The beginning of your calendar - is the day your menstrual flow starts.

Day 7

  • By Day 7 your egg is preparing to be fertilized by sperm.

Days 11 - 21

  • Between Days 11-21 hormones in your body cause your ovary to release an egg. The egg travels through the fallopian tube towards the uterus. If sperm penetrates the egg, the fertilized egg will attach to the lining of the uterus and begin to grow.
Day 28
  • On or around Day 28 hormone levels drop causing the lining of the uterus to be shed. This lining makes up your menstrual flow.

The Calendar Tracking Method

Estimating Your Fertility Window

Use your past menstrual cycles to help you estimate your fertility window:


What to Do

Step 1

  • Commit to tracking your menstrual cycle for at least 8 months.

Step 2

  • Note Day 1 as the first day you start your period.

Step 3

  • After tracking for 5-6 months, pinpoint the longest and shortest of your cycles.
Step 4
  • Determine your first fertile day by subtracting 18 days from the length of your shortest cycle.

    For example, if 26 days was your shortest menstrual cycle, you'd subtract 18 from 26 to come up with 8. This means that the first day of your fertility window starts on the 8th day of your cycle.
Step 5
  • Determine your last fertile day by subtracting 11 from the length of your longest cycle.

    So if 32 days was your longest menstrual cycle, you'd subtract 11 from 32 to come up with 21. This means that the last day of your fertility period ends on the 21st day of your cycle.

The time in between your first and last fertile days is your fertility window.

Since you’ll ovulate at some point within this time frame, this is when a pregnancy can happen.

If you don’t want to get pregnant, abstain from sexual intercourse or use a barrier method of birth control during your fertility window.


The Basal Body Temperature (BBT) Method

Your basal body temperature rises slightly after ovulation and remains elevated until your next period.

You can estimate when you’ll ovulate by recording your temperature throughout a few of your monthly cycles.

Checking and Recording Your Basal Body Temperature


What to Do

Step 1

  • Take your temperature orally each morning before you get out of bed.

Step 2

  • Use a basal thermometer which recognizes small changes in your temperature.

    Your body temperature rise only between 0.4 and 1 degree Fahrenheit when you ovulate.

Step 3

  • Record you temperature every day on a fertility tracking calendar.

    Before you ovulate your temperature is consistent. But as you get closer to your ovulation date, you’ll see a slight decline followed by a sharp increase after you ovulate. This temperature increase signals that ovulation has just happened.

    At this point, you are more likely to get pregnant. If you don’t want to get pregnant, abstain from sexual intercourse or use a barrier method of birth control.

The Cervical Mucus Method

The consistency of your cervical mucus changes during your menstrual cycle.

On average there are 3 to 4 dry days following a 5-day menstrual flow. Then the mucus increases daily, lasting about 9 days until the wettest day.

By day 9 or 10 you can easily recognize your cervical mucus. It should be abundant, slippery, clear, and stretchy - like egg whites. Ovulation happens on the peak day of this stretchy mucus period.  At this point, you are more likely to get pregnant.  If you don’t want to get pregnant, abstain from sexual intercourse or use a barrier method of birth control.

Checking Your Cervical Mucus

As you chart your cervical mucus don’t douche or use spermicides. These can increase your risk for infection and may wash away or change the appearance of the mucus.


What to Do

Step 1

  • Each day, collect the mucus from your vaginal opening with your fingers by wiping them from front to back.

Step 2

  • On your calendar, make note of the color of the mucus (yellow, white, clear or cloudy); it's  consistency (thick, sticky, or stretchy); and the feel (dry, wet, sticky, slippery).

Step 3

  • Note your ovulation day on the day that your mucus is clearest, slippery and the most stretchy.


Couples who use these natural methods correctly over one year have only a 1% to 9% chance of becoming pregnant. * This means that approximately 10 out of 100 women using only these methods for one year will get pregnant.

* source: American Pregnancy Association


Advantages & Disadvantages



  • No side effects.
  • Inexpensive or free.
  • No devices, no medications, no prescriptions or office visits.
  • Acceptable for couples who have religious concerns related to contraception.
  • Encourages male involvement in family planning.
  • Does not protect against sexually transmitted infections or HIV.
  • Requires commitment, motivation and cooperation from both partners.
  • Requires consistent and accurate record keeping.
  • Is more challenging for women with irregular cycles.

Cautions & Things to Consider

Natural Family Planning Doesn’t Protect Against STIs

NFP won’t protect you or your partner from STIs including HIV/AIDS or Hepatitis B. Using an NFP method and condoms at the same time can reduce your chances of getting an STI, including HIV/AIDS.

Illness and Stress Can Affect Your Cycle

Stress, illness, lack of sleep, and alcohol or drug use can affect your temperature and make it difficult to get an accurate reading of your basal body temperature.

Vaginal infections can cause changes in the mucus of your cervix. These changes might lead you to believe you’re not fertile when you really are, and will increase your chances of getting pregnant.

Loss of Spontaneity

For some, natural family planning means lost spontaneity. Because partners have to wait for infertile days, sex may begin to feel "scheduled".

Will Power and Commitment

Couples who don’t use their method correctly - that is, they have intercourse on days when the method's guidelines tell them that the woman is fertile - -have a much greater chance of unintended pregnancy.

NFP will only work if you and your partner are motivated, consistent, and committed to regular monitoring of your cycle. You must both also have the will power to be abstinent during fertile periods. If you don’t think you can meet any of these demands you should choose another method of birth control.


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Revised: Wednesday April 22 2009

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