The information which follows is a basic overview of the Fertility Awareness Method, to show how it works and how it can help you. You are advised to read Taking Charge of Your Fertility: The Definitive Guide to Natural Birth Control by Toni Weschler for a more detailed explanation.

What is the Fertility Awareness Method?
FAM (or charting) helps a woman to pinpoint when she is most fertile, when ovulation has taken place when she could be pregnant. By predicting fertility in this way, the time taken to conceive can be reduced. A number of physical signs (waking temperature, cervical fluid and cervical position) change within the menstrual cycle and by charting these fertility signs it is possible to determine when ovulation takes place. It is not the ‘rhythm method’ which simply involved counting days, and does not take into account the variations that can occur in a menstrual cycle.

The use-effectiveness rate of FAM (which doesn’t assume perfect use) is around 90%. This means that 1 in 10 women who use FAM as their sole method of birth control will have an un-planned pregnancy during one year – this is similar to the use-effectiveness rate of the male condom. If you were to use FAM as your sole method of birth control for 10 years, one un-planned pregnancy would be expected.

How does it work?
A woman’s egg only lives for about 24 hours, whilst under optimum circumstances, sperm may live in the uterus and fallopian tubes for up to 6 days (2-3 days is more usual). The aim of FAM is to predict when the ‘window of fertility’ will occur, using a number of fertility indicators.

Although highly complex, the rhythm of a woman’s fertility cycle is easily plotted. Fertility Awareness works by analyzing just a few easily observable signs of the woman's body. In a nutshell, a woman's fertility cycle operates according to a predictable rhythm with specific signs that identify where in the cycle she is. A clear example is menstruation, while less obvious signs are changes in waking temperature and the quality of cervical fluid. Changes in cervical position also indicate fertility, but can be harder to interpret – for this reason, cervical position is generally only used in FAM to backup the primary indicators of fertility.

The minimum information needed to track fertility is menstruation and waking temperature. Keeping a note of changes in your cervical fluid will also allow you to predict ovulation whereas temperature changes will only confirm when ovulation has taken place after the event. As an absolute minimum in the practice of fertility awareness, you only need to keep track of two of the four listed above: menstruation and temperature.

Fertility Indicators
1) Menstruation
While menstruation is in reality the end of a cycle (shedding the lining of the uterus that has built up during the previous cycle), in FAM it is viewed as the first day of the new cycle, as it is so easy to identify.

2) Waking Temperature
During the night your body temperature gradually reduces, and then raises again as you move towards waking up. The drop varies from person to person, but all people do experience it. Your temperature on waking is one of the key indicators of fertility. When a woman ovulates, progesterone is released into the body. One of the effects of this hormone is to slightly raise your waking temperature, typically by about 0.2 to 0.4° Fahrenheit / 0.1 to 0.2° Celsius over several days. To detect this change, you will need to purchase a basal thermometer, which is available from most chemists. A standard thermometer will not be accurate enough to pick up the slight change.

Ovulation is indicated by noting three temperatures that rise at least 0.2° F / 0.1° C above the previous six temperatures. A "coverline" is drawn 0.1° F / 0.05° C above the highest of these six temperatures and when three successive temperatures are above this line, there is a good chance that you have ovulate. (This is a simplification of the identification of the coverline - please refer to Taking Charge of Your Fertility for a more detailed explanation)

Waking temperature is an excellent indicator that ovulation has occurred, but if you are charting in order to improve your chances of becoming pregnant, then it is important to note changes in your cervical fluid as well.

3) Cervical Fluid
Cervical fluid is an important sign in fertility awareness. As ovulation approaches, the amount of oestrogen in your body increases, which causes the body to secrete more cervical fluid, and makes the fluid stretchy and clear. After ovulation, oestrogen levels decrease again, and this causes the cervical fluid to dry up.

Cervical fluid is a good indicator that fertility is increasing - it provides an excellent pre-ovulation indicator, whereas temperature alone can only indicate ovulation after it has happened.

As your cervical fluid changes, you may notice the following different qualities -

• Sticky – A less fertile-type of fluid, not very conducive to supporting either sperm motility or lifespan.
• Creamy – A lotion-like type of fluid, which can support sperm for longer periods than the sticky-quality type.
• Eggwhite – The most fertile quality cervical fluid, it is clear, stretchy, and slippery. This type of cervical fluid resembles raw eggwhite, hence the descriptive name. This may correspond to a Lubricative vaginal sensation.

4) Cervical position
As ovulation approaches, rising levels of oestrogen cause changes in the position, texture, and opening of the cervix. During the infertile phases of your cycle, your cervix is low, firm and closed, to reduce the risk of infection. As fertility increases, your cervix will become softer, start to open and to rise in position. This is to make it easier for sperm to reach your egg. Your cervix opens slightly during your period to allow the menstrual flow through.

Identifying the phases of your cycle

Phase 1 - The Pre-ovulatory Low Fertility Phase
It is generally easy to identify the first day of Phase 1, as it is the first day of menstruation. Phase 1 is generally infertile, but as you get closer to the end of it, fertility does rise slightly due to the fact that you are close to ovulation. Pregnancy may result from sex as far as 5 days before ovulation

Phase 2 – The Fertile Phase
The start of Phase 2 is determined by the appearance of ANY cervical fluid. This is because cervical fluid extends the life expectancy of sperm, and increases the possibility of conception. On the other hand, sex is unlikely to result in conception if there is no cervical fluid. The quantity, colour and consistency of cervical fluid change as ovulation approaches. The "less fertile" type of cervical fluid is sticky, crumbly or creamy/opaque, the "more fertile" type is like raw eggwhite (wet, stretchy, slippery, and clear) although it is possible to conceive without seeing the Eggwhite type fluid.

Phase 3 – The Post-Ovulatory Infertile Phase
It is possible to identify the start of the third phase based on temperature changes alone, or more easily through a combination of temperature shift and changes in cervical fluid.

FAM requires there to be a significant increase in waking temperature for at least 3 consecutive days over the previous 6 days. To determine when this has been done, a coverline is drawn 0.1° F (0.05° C) above the highest of the six pre-shift temperatures. Once 3 or more temperatures have been noted above the coverline, a temperature shift can be said to have taken place.

Once in Phase 3, you are infertile until the start of Phase 2 – you may chose to stop noting your temperatures until your period starts. However, if you are charting to improve your chances of becoming pregnant, you may wish to continue charting your temperature. Your temperature will drop again either just before or on the day that your period starts, and a run of 18 temperatures above the coverline will indicate that you are pregnant.

How to chart
You need to purchase a basal thermometer (also known as a fertility thermometer) – you can get these from most chemists, but be aware that Boots tend to keep them behind the counter, so you will need to ask for them.

Your cycle is classed as starting on the first day of heavy flow of your period. Do not count any days where you have spotting – once your period has properly started, you can start charting your temperature. You need to take your temperature as soon as you wake up, after at least 3 consecutive hours sleep, but before you go to the toilet, have a drink, check on the baby etc. A number of factors can influence your waking temperature, including illness, disruptions to your sleep, drinking alcohol the night before etc. You need to make a note if any of these factors apply on a given day.

You can record your fertility indicators either in a paper based system, in which case you will need to work out a coverline for yourself, or using fertility awareness software.

If you plan to use fertility software, which will calculate the coverline and ovulation day for you, then visit either www.tcoyf.com or www.fertilityfriend.com for more details of this.

If not using software, you can learn the various rules of charting by reading Taking Charge of Your Fertility: The Definitive Guide to Natural Birth Control or by taking classes from a certified FAM practitioner. Printed charts can be downloaded by clicking here.