Fertility Awareness: Natural Family Planning (NFP)
What is fertility awareness?
Fertility awareness is a collection of methods using your body's natural and normal functioning to determine
the days of the month you are most likely to get pregnant. It is also called Natural Family Planning (NFP), the
Sympto-Thermal Method, the Ovulation Method, or the Billings Method.
Fertility awareness or Natural Family Planning is a method of birth control that does not use any drugs or
devices. It combines the calendar/rhythm method, the basal body temperature method, and the cervical mucus
The fertility awareness method is used both as a means of preventing pregnancy as well as targeting the most
fertile time for getting pregnant.
How does fertility awareness work?
The calendar; basal body temperature; and cervical mucus methods are combined to give you the awareness of
when your body is most fertile. As you become familiar with your body's ovulation and fertile periods, it
provides you the opportunity to abstain from sexual intercourse or use one of the barrier methods during that
How do you use fertility awareness?
The first objective within fertility awareness is to become familiar with your menstrual cycle and to begin
charting your fertility pattern. The average menstrual cycle is between 28 to 32 days, however there are two
parts related to your cycle: before ovulation and after ovulation. Here is a glance at an average cycle to give
you a gauge for examining your cycle:
Day 1: The first day of your menstrual flow is the beginning of the calendar.
Day 7: By day seven your egg is preparing to be fertilized by sperm.
Days 11-21: (based on 28-day cycle) Hormones in your body cause the egg to be released from the ovary around
this time. This process is known as ovulation. 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. If
fertilization does not happen the egg breaks apart.
Day 28: Hormone levels drop around this day causing the lining of the uterus to be shed making up your
It is important to realize that the first part of the menstrual cycle (before ovulation) is different in
every woman and can even change from month to month. The variation usually occurs from 13 to 20 days long. The
last half of the cycle is usually more similar for every women, because there are about 14 days from day of
ovulation until the start of the next period. This is why women are encouraged to track their cycles and count
back 14 days from their LMP to narrow down their most fertile time of the month.
Calendar tracking method: Your past menstrual cycles will work as a guide for estimating
your fertile times. In order to track your menstrual cycle and to identify your expected ovulation follow the
step by step process below:
Step 1: Plan on tracking your menstrual cycle for 8 to 12 months.
Step 2: Day 1 will be the first day you start menstruation.
Step 3: Pick the longest and shortest of the cycles from your monthly tracking.
Step 4: The first day of your fertility period is determined by subtracting 18 days from the length of your
shortest cycle. If 26 days was your shortest menstrual cycle, take 26 and subtract 18 to come up with the
number 8. This means that the first day of your fertility window starts on the 8th day of your cycle.
Step 5: The last fertile day is determined by subtracting 11 from the length of your longest cycle. If 32
days was your longest menstrual cycle, take 32 and subtract 11 to reach the number 21. This means that the last
day of your fertility period ends on the 21st day of your cycle.
The time in between these two days is considered your fertility window. In the above example, your fertility
period would be from the 8th day of your cycle to the 21st day of your cycle. Your ovulation is expected during
this time frame. You cannot get pregnant everyday during this period, but it is sometime during this period
that pregnancy can occur.
If you are trying to avoid getting pregnant, you need to abstain from sexual intercourse or use a barrier
form of birth control during your fertility window. If you are trying to get pregnant, this fertility period
would be the targeted time for sexual intercourse.
Basal body temperature method: Your basal body temperature measures a change in the
temperature that occurs after ovulation and remains elevated until your next period. By looking at charting
from a few cycles, the temperatures can reveal a pattern from which ovulation can be anticipated. The steps
below can help you as you begin to track your temperature and identify when you are ovulating.
Step 1: Take your temperature orally each morning before you become active.
Step 2: Use a basal thermometer which recognizes small changes in your temperature. Your body temperature
will only rise between 0.4 and 1 degree ferenheit when you ovulate. Buy a Basal Thermometer Now.
Step 3: Record you temperature every day on your fertility tracking calendar.
If you record it every day, you will see that prior to ovulation your temperature is rather consistent. As
you get closer to ovulation, you may have a slight decline, but it will be followed by a sharp increase after
ovulation. The increase in temperature is the sign that ovulation has just occurred. Because the increase
happens after you have ovulated, this method is best used by those who have time to track and study
their charts for a couple months, to ensure the best chances of conception. Illness, lack of sleep, and alcohol
or drug use can affect your temperature and make it difficult to establish an accurate reading.
Cervical mucus method: The consistency of your cervical mucus changes during the menstrual
cycle. In the average cycle, there are 3 to 4 dry days following a 5 day menstrual flow.
The mucus wetness increases daily, lasting approximately 9 days until the wettest day. Your mucus is easily
recognized at this point. It should be abundant, slippery, clear, and very stretchy. It has been described as
Ovulation occurs when you have your peak day of stretchy mucus (within two days). In order to use the
cervical mucus method to identify your ovulation follow the few steps noted below:
Step 1: Collect the mucus from the vaginal opening with your fingers by wiping them from front to back.
Step 2: Record it daily on your fertility calendar by making note of the color (yellow, white, clear or
cloudy), the consistency (thick, sticky, or stretchy) and the feel (dry, wet, sticky, slippery, stretchy).
Step 3: Ovulation is recorded on the day that your mucus is clearest, slippery and most stretchy.
Do not douche or use spermicides which increase your risk for infection and may wash away or change the
appearance of the mucus.
How effective is fertility awareness?
When fertility awareness is used correctly and consistently, it may reach effective rates around 90%. The
effectiveness depends on your diligence to track and record your fertility pattern and your commitment to
abstaining from sexual intercourse or using a barrier form of birth control during your fertility window.
Typical use, which refers to the average use, shows a failure rate of approximately 25%. If you are
committed to tracking and recording your fertility information, you can achieve much higher success rates.
What are the side effects or health risks of fertility awareness?
There are no health risks or side effects associated with fertility awareness.
Is fertility awareness reversible?
Yes. Fertility awareness does not have any effects on the male or female reproductive functioning. Pregnancy
is possible immediately following the practice of fertility awareness.
How much does fertility awareness cost?
Fertility awareness is free to inexpensive. Free training sessions are usually available around your
community through health centers, pregnancy services, or some churches. Thermometers used to measure basal body
temperatures cost between $10 and $15 and are available at local drugstores, grocery stores or supercenters.
You may use one of your home calendars to record this information, or you can purchase a fertility awareness
chart which cost approximately $8.
What about fertility awareness and sexually transmitted diseases
Fertility awareness does NOT provide any protection against sexually transmitted diseases.
Are there any other physical signs of ovulation?
Your fertility period may be identified by paying attention to other functions of your body. Fertility and
ovulation are sometimes tracked or noticed by women who:
- Experience a change in the cervix
- Have a slight one-sided pain in the area of an ovary
- Softening of the cervix
- Breast tenderness
Fertility awareness is an acceptable means of birth control for couples who have religious concerns related
Fertility awareness is also used by couples who are trying to get pregnant. It helps you target your
reproductive efforts at the best times to get pregnant.
What are the pros and cons of fertility awareness?
The Pros of Fertility Awareness include:
The Cons of Fertility Awareness include:
- Requires diligence from both partners
- Requires periods of abstinence or backup contraception for approximately
1/3 of the month
- Requires consistent and accurate record keeping
- More challenging for women with irregular cycles
View and print an Ovulation Calendar, or use our Ovulation Calculator, to better understand your
menstruation cycle and ovulation.