A couple voluntarily avoids sexual intercourse during the
fertile phase of the woman’s cycle (time when the woman can become pregnant) or has
intercourse during the fertile phase to achieve pregnancy.
Types
Calendar (Rhythm) Method — least effective, Basal Body Temperature, Cervical Mucus
Method (Billings) and Symptothermal Method (BBT + cervical mucus) — most effective
Mechanisms of Action
For Contraception
Intercourse is avoided during the phase of the menstrual cycle when conception is most
likely.
For Conception
Intercourse is planned for near the mid-cycle (usually days 10–15), when
conception is most likely.
Benefits
Contraceptive
- Can be used to avoid or achieve pregnancy
- No method-related health risks
- No systemic side effects
- Inexpensive
Noncontraceptive
- Promote male involvement in family planning
- Improve knowledge of reproductive system
- Possible closer relationship for couple
Limitations
- Moderately effective as a contraceptive (9–20 pregnancies per 100 women during the
first year of use)
- Effectiveness depends on willingness to follow instructions
- Considerable training required to use the most effective types of NFP correctly
- Require trained provider (nonmedical)
- Require abstinence during fertile phase to avoid conception
- Require daily record keeping
- Vaginal infections make cervical mucus difficult to interpret
- Basal thermometer needed for some methods
- Do not protect against STDs (e.g., HBV, HIV/AIDS)
Who Can Use Natural Family Planning
For Contraception
- Women of any reproductive age
- Women of any parity including nulliparous women
- Couples with religious or philosophical reasons for not using other methods
- Women unable to use other methods
- Couples willing to abstain from intercourse for more than 1 week each cycle
- Couples willing and motivated to observe, record and interpret fertility signs
For Conception
- Couples trying to achieve pregnancy
Conditions Requiring Precautions
CONDITION |
RECOMMENDATION |
| Irregular menses |
If using calendar method, counsel and help client
choose another method. |
| Persistent vaginal discharge |
Counsel client that it will be more difficult to
predict fertility using the cervical mucus method. If client wishes, help her choose
another method. |
| Breastfeeding |
Counsel client that it will be more difficult to
predict fertility using the cervical mucus method. If client wishes, help her choose
another method. |
Who Should Not Use NFP
- Women whose age, parity or health problems make pregnancy a high risk
- Women without established menstrual cycles (breastfeeding, immediately postabortion)
- Women with irregular cycles (calendar method only)
- Women whose partner will not cooperate (abstain) during certain times in the cycle
- Women who dislike touching their genitals
Client Instructions
Calendar Method
You can determine your fertile period by monitoring your menstrual cycles.
For Contraception
Calculate Your Fertile Period:
- Monitor the length of at least 6 menstrual cycles while abstaining or using another
contraceptive method. Then calculate when the fertile days occur following the
instructions below.
- From the number of days in your longest cycle, subtract 11. This identifies the last
fertile day of your cycle.
- From the number of days in your shortest cycle, subtract 18. This identifies the first
fertile day of your cycle.
| Example: |
Longest cycle: 30 days minus 11 = 19
Shortest cycle: 26 days minus 18 = 8 |
- Your fertile period is calculated to be days 8 through 19 of your cycle (12 days
of abstinence needed to avoid pregnancy).
- Abstain from sexual intercourse during the fertile days.
For Conception
Have intercourse during the fertile days.
Basal Body Temperature (BBT) Method
You can determine your fertile phase by taking accurate measurements with a special
thermometer to detect even a slight increase in your temperature.
Use the Thermal Shift Rule
- Take your temperature at about the same time each morning (before rising) and record the
temperature on the chart provided by the NFP instructor.
- Use the temperatures recorded on the chart for the first 10 days of your menstrual cycle
to identify the highest of the "normal, low" temperatures (i.e., daily
temperatures charted in the typical pattern without any unusual conditions). Disregard any
temperatures that are abnormally high due to fever or other disruptions.
- Draw a line 0.05–0.1°C above the highest of these
10 temperatures. This line is called a cover line or temperature line.
- The infertile phase begins on the evening of the third consecutive day
that the temperature stays above the cover line (Thermal Shift Rule).
For Contraception
Abstain from sexual intercourse from the beginning of the menstrual period until the
evening of the third consecutive day that the temperature stays above the cover
line.
Notes:
- If any of the 3 temperatures falls on or below the cover line during the 3 day count,
this may be a sign that ovulation has not yet taken place. To avoid pregnancy, wait until
3 consecutive temperatures are recorded above the cover line before resuming
intercourse.
- After the infertile phase begins, it is not necessary to keep taking your temperature.
You may stop until the next menstrual cycle begins and continue to have intercourse until
the first day of the next menstrual period.
For Conception
Have intercourse during the fertile days.
Cervical Mucus Method
You can determine your fertile phase by monitoring your cervical mucus.
A simple, accurate record is the key to success.
A series of codes is used to complete the record. These codes should be both
appropriate to the local culture and widely available to NFP users. In some areas, colored
stamps or inks are used; in others, it is more convenient to develop symbols that are
written by hand; while in still others, both methods are combined resulting in handwritten
symbols that are recorded with colored pens. Examples of two systems are given below.
Examples of Codes Used in Fertility Record Keeping
Use the symbol * or red to show bleeding.
Use the letter D or green to show dryness.
Use the letter M with a circle around it or leave blank to show wet, clear,
slippery, fertile mucus.
Use the letter M or yellow to show sticky, white, cloudy, infertile mucus.
Definitions
- Dry Days: After menstrual bleeding ends, most women have 1 to a few days in which
no mucus is observed and the vaginal area feels dry. These are called dry days.
- Fertile Days: When any type of mucus is observed before ovulation, you are
considered to be fertile. Whenever mucus is seen, even if the mucus is of a sticky, pasty
type, the wet fertile mucus may be present in the cervix and the fertile days have
started.
- Peak Day: The last day of slippery and wet mucus is called the peak day;
it indicates that ovulation is near or has just taken place.
For Contraception
- As mucus may change during the day, observe it several times throughout the day. Every
night before you go to bed, determine your highest level of fertility (see list of codes)
and mark the chart with the appropriate symbol.
- Abstain from sexual intercourse for at least 1 cycle so that you will know the mucus
days.
- Avoid intercourse during your menstrual period. These days are not safe; in short
cycles, ovulation can occur during your period.
- During the dry days after your period, it is safe to have intercourse every other night
(Alternate Dry Day Rule). This will keep you from confusing semen with cervical
mucus.
- As soon as any mucus or sensation of wetness appears, avoid intercourse or sexual
contact. Mucus days, especially fertile mucus days, are not safe (Early Mucus Rule).
- Mark the last day of clear, slippery, stretchy mucus with an X. This is the peak day. It
is the most fertile time.
- After the peak day, avoid intercourse for the next 3 dry days and nights. These
days are not safe (Peak Day Rule).
- Beginning on the morning of the fourth dry day, it is safe to have intercourse until
your menstrual period begins again.
For Conception
- Have intercourse during each cycle on the days when your vaginal discharge feels
elastic, wet and slippery.
Symptothermal Method—You should have instructions for both the Cervical Mucus and
Basal Body Temperature methods.
You can determine your fertile days by monitoring both your temperature and your
cervical mucus.
- After menstrual bleeding stops, you may have intercourse on the evening of every other
dry day during the infertile days before ovulation. This is the Alternate Dry Day Rule,
the same rule used with the Cervical Mucus Method.
- The fertile phase begins when wet vaginal sensations or any mucus is experienced. This
is the Early Mucus Rule, the same rule used with the Cervical Mucus Method. Abstain
from intercourse until the fertile phase ends.
- Abstain from intercourse until both the Peak Day and Thermal Shift
Rules have been applied.
- When these rules do not identify the same day as the end of the fertile phase, always
follow the most conservative rule, that is, the rule that identifies the longest
fertile phase.
The following example refers to the Completed Basal Body Temperature Chart (see
above). Following the Thermal Shift Rule, the woman is infertile after day 16. If,
however, she follows the Peak Day Rule, she is not infertile until the 18th day.
Therefore, she should use the conservative rule, the Peak Day Rule, and wait until
the 18th day before resuming intercourse.
Note: You may have intercourse during the first 5 days of the menstrual cycle
beginning with the first day of menstrual bleeding, if the Peak Day and Thermal
Shift Rules were applied during the previous cycle. This is referred to as the Menses
Rule and ensures that this is truly menstrual bleeding and not due to some other
cause.
Who Can Provide
- Physicians
- Nurses, Midwives, Paramedics
- Nonmedical Staff
- Staff specially trained in NFP must be available.
Where They Can Be Provided
- Hospitals
- Clinics
- Health Posts
- Private Offices
 
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