Natural Family Planning Method

Dr. Vilma Ruddock
OBGYN appointment

Natural family planning is an option for women who want to avoid getting pregnant without using artificial forms of birth control. The method relies on keeping track of events that change during the fertile days of the menstrual cycle close to ovulation. It also helps women who are trying to conceive to ensure they have intercourse when they are most fertile.

What Is Natural Family Planning?

Natural family planning uses one or more fertility awareness methods to predict the days of peak fertility around ovulation. By close observation, women who want to prevent pregnancy by natural means can know which days to avoid intercourse each menstrual cycle. This family planning method is based on:

  • Knowledge of the hormonal events of the menstrual cycle and signs of fertility in the cervix and body temperature near ovulation
  • The lifespan of the sperm, which can survive in a woman's reproductive tract for three and sometimes up to five days after ovulation
  • The lifespan of the egg, which lasts 12 to 24 hours after ovulation; the chance of conception is zero after 24 hours

According to a 1995 study in the New England Journal of Medicine, women are most likely to conceive if they have intercourse during the five days before and on the day of ovulation - the six days of the so-called fertile window. To be safe, continue to avoid sex for two to three days after any method of estimated day of ovulation.

The Fertility Awareness Methods

The fertility awareness methods of natural family planning include tracking changes in the cervical mucus, physical changes in the cervix, basal body temperature, and estimating the fertile window based on menstrual cycle lengths. Easy training by medical personnel or online instruction will improve your confidence in monitoring these signs.

The Cervical Mucus Method

The cervical mucus method tracks changes in your cervical mucus that indicate when you are most fertile. As you get closer to ovulation, the glands in your cervix produce more mucus due to increasing estrogen from your ovaries. To use the cervical mucus fertility awareness method:

cervical mucus
  1. Start checking the mucus on your underwear daily starting the day after your period ends. At this time you should notice little to no cervical mucus, but you will begin to feel wetter a few days before ovulation.
  2. Try to collect some of the mucus secretions from outside your vaginal opening with your fingers for inspection. You can also insert one or two fingers inside your vagina to scoop out some mucus for examination.
  3. Your fertile window starts the day you begin to feel wet or notice thinner, more watery mucus. If you don't want to get pregnant, avoid intercourse starting that day.
  4. Continue to avoid intercourse on the following days as your mucus increases and gets more watery and slippery and goes from creamy or white to resemble clear raw egg white or K-Y Jelly. Try to stretch your mucus between two fingers (known as the spinnbarkeit).
  5. These qualities are greatest a day or two before you ovulate, and you are most fertile on those two days but especially on the day of ovulation. Sperm swim up easier in this type of mucus to reach your fallopian tubes and egg.
  6. Your fertile window ends when your mucus dries up again and becomes thick, gummy, or gluey, and loses its spinnbarkeit, and sperm can't spin through. This occurs about 24 hours after you ovulate due to increased progesterone.

A study reported in 1990 in Family Planning Perspective found that, if done accurately, this method has only a 3.1 percent risk of pregnancy.

The TwoDay Cervical Mucus Method

With the TwoDay cervical mucus method, you also check mucus daily, but you focus on the presence of mucus secretions on two days.

  • Observe if you have secretions today and recall if you noticed secretions yesterday.
  • You are in your fertile window when you are wet or have mucus secretions on either day and until you no longer have any mucus.

A 2004 Fertility and Sterility study found that the TwoDay method was accurate in identifying the fertile days of the cycle 96 percent of the time.

Physical Changes in the Cervix

For most of the menstrual cycle, your cervix is firm (feels like the tip of your nose), the opening is narrow, and you can reach your cervix when you insert a finger in your vagina. Three physical changes helps you to identify your approaching ovulation:

  1. Your cervix gets softer.
  2. Your cervical opening gets wider to make it easier for sperm to swim through.
  3. Your cervix sits higher in your vagina so it is harder to reach with your finger.

When you start to detect these changes, your fertile time begins and ends when your cervix gets firm, closed, and sits lower in your vagina. This is not an easy fertility method to master but if you practice every day, you can improve your skill at detecting these changes in your cervix.

The Standard Days Method

menstrual cycle

The standard days method sets specific days in your cycle during which you are considered most fertile. The method works best if your cycles are 26 to 32 days long, according to the Journal of Midwifery and Women's Health. You can keep track of your menstrual cycles on a calendar or a menstrual cycle chart. The method works as follows:

  1. Day one of your cycle is the first day of your period. Start counting from that day.
  2. Your standard fertile window is set at day 8 to day 19 of your cycle. Avoid unprotected intercourse during those 12 days.
  3. You are safe to have unprotected intercourse days 1 to 7 and can resume on day 20 after your fertile days end.

If done right, the standards days method is at least 95.2 percent effective in preventing pregnancy according to a study published in 2002 in Contraception. You can use color-coded CycleBeads® on a string to help you keep track of your cycle. There is also a CycleBeads iTunes mobile app that simplifies tracking your standard fertile days.

The Calendar-Based Method

The calendar-based fertility awareness method is based on keeping track of your menstrual cycle lengths over several cycles to calculate the range of your fertile window:

  1. Record your periods on a calendar or menstrual cycle chart.
  2. Count the number of days in your menstrual cycles from day one of bleeding to day one of your next period. This gives you the length of a cycle.
  3. Next, pick your shortest cycle length and subtract 18 days to get the day your fertile time begins.
  4. Then, pick your longest cycle and subtract 11 to find the last day of your fertile period.
  5. For example, if your cycles are 25 to 35 days long, you should not have unprotected sex during days 7 to 24 of your cycle to avoid the risk of getting pregnant the day you ovulate during that time:
    • 25 days - 18 = day 7 of your cycle
    • 35 days - 11 = day 24 of your cycle

If your cycle lengths vary, the calendar method covers you for when your cycle is short and you ovulate early, and for when your cycle is long and you ovulate later in your cycle. If your cycles are regular and average 28 days long, your fertile phase will last from days 9 to 17.

Basal Body Temperature Method

The basal body temperature (BBT) fertility awareness method uses the increase in your basal or resting body temperature the day after ovulation to identify when you are most fertile in your menstrual cycle.

The following information will help you estimate the day you likely ovulate in a cycle and understand how the method works. For the best data, chart your BBT over at least three menstrual cycles or more to see your pattern of ovulation.

  1. Starting on the day your period until the start of your next period, take your temperature daily first thing in the morning before getting out of bed or any other activity.
  2. Mark the daily reading on a BBT chart.
  3. Your BBT stays below 98 degrees Fahrenheit before ovulation and rises above 98 degrees a day after because of an increase in progesterone. Elevation of the BBT above 98 degrees for at least three days is greater evidence ovulation occurred.
  4. You are most fertile for the two to three days before the shift in your basal body temperature.
  5. Your temperature will stay elevated until the day your next period starts, about 12 to 14 days after you ovulate.

Because your BBT rise doesn't happen until after ovulation, you cannot use this method to help you know when to avoid sex during the current cycle. However, if your cycles are regular, the BBT charting will give you an idea when you might expect to ovulate during the following menstrual cycles and when to avoid sex.

BBT chart

The Symptothermal Method

Combining the BBT method with other fertility awareness methods improves the accuracy of estimating the days you are most fertile. The so-called symptothermal method combines the BBT method with the cervical mucus method as one natural family planning method. A 2007 study in Human Reproduction found the combination is 99.4 percent effective in preventing pregnancy

You can also combine the BBT method with the TwoDay cervical mucus method, or with the Standard Days method. Matching up the rise in your BBT with your other methods on a chart will improve your estimation of the timing of ovulation. For example, you should see your most fertile mucus a day or two before your temperature shifts above 98 degrees Fahrenheit.

Recording Your Information

There are a variety of ways to record and keep track of your information including using an ordinary paper or a digital calendar or fertility charts. Recording all your fertility signs on one chart makes it easier to see the pattern of when you are most fertile.

A Downloadable Printable Chart

This printable LoveToKnow natural family planning chart is an efficient way to record all your fertility awareness observations and keep track of the length of menstrual cycles. Click on the image to download, save, and print the PDF file. Follow these instructions if you need help with downloading Adobe PDF files.

Natural family planning chart

To use the family planning chart:

  • Following the instructions at the bottom of the chart, record your fertility awareness data on the appropriate cycle day.
  • Use one printed chart per menstrual cycle.
  • If your cycle is longer than 40 days, continue your input on a second chart, changing the cycle day numbers to 41, etcetera.

Fertility Tracking Apps

There are useful digital fertility apps available you can use to record your observations and keep track of your fertile days. Options include the following.

  • Lady Cycle and Ovulation and Fertility Tracker are two free android-compatible apps you can download from Google Play.
  • Lily - Fertility Calculator is compatible with iPhones and other iOS devices. Download it free from the iTunes App Store.
  • Sympto - This natural family planning manager can be used on iPhones and other iOS devices, as well as android devices and through web browsers. The free version has ad messages, but you can pay for an ad-free version.

These apps are convenient for charting and displaying your information. However, to estimate the days your are fertile, it is important to rely mainly on your personal observations and not solely on any calculations made by an app.

A Valuable Birth Control Method

Natural family planning is a valuable birth control method for many women, especially those in developing countries who are without access to other forms of contraception. It also benefits women whose religions oppose artificial forms of birth control. Women who want to get pregnant can also use the method to make sure they have intercourse during the most fertile days of their menstrual cycle.

Natural Family Planning Method