Advantages

• It is a totally natural approach, involving no chemicals
• It allows women to be in touch with their own body and its changes
• It can be used to either avoid or to plan a pregnancy
• With strict adherence to the rules, it is effective
• It best suits couples in committed, cooperative relationships.

Disadvantages:

• It may take up to 6 cycles to learn effectively
• There are extended periods when intercourse is avoided and this may correspond to a time when a woman's libido is strongest
• Daily records need to be kept
• Indicators of fertility may be changed by events such as illness, having sex and stress
• Both the woman and her partner need to co-operate; this requires lengthy periods of planned abstinence (not having sex)
• There is no protection against sexually transmitted infections.

What is a Normal Menstrual Cycle?

A cycle is defined as the length of time from the start of one period until the start of the next; the first day of a menstrual period is defined as day one. For a woman with a 28 day cycle, an egg will usual be produced (ovulation) sometime between day 11 and day 17; the release of the egg is reponsible for the timing of the next period. An egg will survive for only 24 hours and the next period will usually come 11-17 days later. Sperm usually survive for 3 days but occasionally may survive up to 7 days. A woman may fall pregnant anywhere from day 4 to day 18.

What Works and What Doesn't

The Rhythm Method

This involves calculating the safe days from the expected timing of periods. This is NOT a recommended method as even women who have their periods "like clockwork" may have an early or late ovulation and hence a fertile time that is different than expected. This may occur for all sorts of reasons and is impossible to predict in advance.

Temperature

The body temperature rises shortly after ovulation and will stay high until the next menstrual period. If pregnancy occurs it will remain high. Take your temperature vaginally or orally before you get up every morning (preferably using a digital thermometer).

The rise will be at least 0.2 degrees C but may be as high as 0.5 degrees C.

You are no longer fertile when you have recorded temperatures for 3 days in a row that are higher than all the previous 6 days.

It is important to remember that temperatures may fluctuate for all sorts of reasons such as taking painkillers, having a cold or even sleeping in.

Mucous Changes:

The cervix (which connects the top of the vagina to the uterus) produces mucus that changes over the time of the menstrual cycle.

Immediately after your period you will notice that there is no mucus or scant flaky mucus and there is a dry sensation on the vulva ( skin outside the vagina).

Women with short cycles the mucus may be noticeable immediately and in women with longer cycles, the presence of mucus may be delayed.

Once mucus begins to appear in your cycle this means that you are entering your fertile time. The vulva feels wet and initially the mucus may be moist and sticky and may be white and cloudy.

Over the next few days the mucus becomes more watery, clear and elastic (often referred to as having a raw egg white appearance). At this time a piece of mucus can be stretched between two fingers without breaking. The day of highest mucus production is known as 'the peak'. This is the time of peak fertility and is often only recognised retrospectively..

Shortly after ovulation, the mucus changes and become thicker, more cloudy and breaks easily when stretched. This corresponds with a rise in body temperature and the sensation at the vulva is dry.

Commercially Available Ovulation Predictors:

These tests generally use urine to measure a hormone that rises for a brief period of time just before ovulation. They are expensive and are best for women trying to increase their chances of becoming pregnant.

Which Method Is Best?

A combination of keeping track of mucus patterns and temperature is recommended as the most reliable of the natural methods. Temperature readings on their own can miss the early fertile period and mucus can be altered by sexual excitement, infections, the presence of semen or menstrual blood can mimic and/or conceal the effects of fertile mucus and make signs difficult to interpret.

How Do I Avoid Getting Pregnant Naturally?

• Avoid sex until the menstrual cycle is finished. In women with short cycles, mucus production may start during the menstrual period without being recognised, as the menstrual blood conceals the presence of early fertile mucus.
• Once the period is finished, sex may be had on alternate nights until the first appearance of fertile mucus.

Then

• On the first appearance of the fertile mucus, sex should be avoided until 4 days after the "peak" mucus secretions. This should coincide with recorded temperatures being higher for 3 days in a row (see Temperature)
• In the days before ovulation, sex is avoided first thing in the morning as there may have been an unnoticed mucus change overnight.

Does It Work?

When you stick to the rules, it is 98% effective. But only if you have sex when the rules say it is OK (and unfortunately that can mean not having sex when your libido is strongest). Some women combine natural family planning with barrier methods such as condoms and diaphragms to decrease their chances of becoming pregnant.

And If I Ignore the Rules?

Emergency contraception is available over the counter from a pharmacy without a prescription, within 120 hours of having sex. It is best taken as soon as possible.

Page maintained by:FPV Webmaster
Last updated:20/02/2007
© Family Planning Victoria