Natural family planning (NFP)

Fertility awareness involves being able to identify the signs and symptoms of fertility during the menstrual cycle so you can plan or avoid pregnancy in a natural way.

What is the Menstrual Cycle?

The menstrual cycle is the time from the first day of your period to the day before your next period starts. The average length of the menstrual cycle is around 28 days, although many women have longer or shorter cycles and this is normal. Regardless of how long or short the cycle is, ovulation (when the ovaries release an egg) will usually happen around 10–16 days before the start of the next period.

During your menstrual cycle the following steps occur:

• Eggs develop in your ovaries and usually one is released
• The mucus in the cervix (entrance to the womb) changes to allow sperm to pass more easily through the cervix to reach the egg
• The lining of the womb thickens to prepare for a possible pregnancy
• If the egg is not fertilised by sperm and you don’t get pregnant the womb sheds its lining as your period, which signals the beginning of a new menstrual cycle.

How Does Natural Family Planning Work?

Natural family planning works by observing and recording your body’s different natural signs or fertility indicators on each day of your menstrual cycle. The main fertility indicators are:

• Recording your body temperature
• Monitoring cervical secretions (cervical mucus)
• Calculating how long your menstrual cycle lasts.

Changes in these fertility indicators can help you to identify your fertile time. Some women rely on using only 1 of these fertility indicators. Other women use 2 or more indicators. The more indicators you use, the more effective the method is. You can also use fertility monitoring devices such as the Persona to help you.

How Long does the Fertile Time Last?

The fertile time lasts for around 8 to 9 days of each menstrual cycle. This is because the egg lives for up to 24 hours and sperm can live inside a woman's body for up to 7 days. This means that if you have sex as much as 7 days before the egg is released you may still get pregnant.

How Effective is Natural Family Planning?

If used properly, natural family planning methods are up to 98% effective, depending on which method is used. This means that up to 2 women in 100 will get pregnant in a year. If natural family planning methods are not used according to instructions, more women will get pregnant. Some people choose to combine their fertility awareness knowledge with male or female condoms – this is sometimes known as the fertility awareness combined method.

What are the Advantages of Natural Family Planning?

• Using fertility awareness makes you more aware of your fertility and can help to plan a pregnancy or to avoid a pregnancy
• It does not involve using any chemicals or physical products
• There are no physical side effects
• It is acceptable to all faiths and cultures

What are the Disadvantages of Natural Family Planning?

• It takes 3 to 6 menstrual cycles to learn effectively
• You have to keep daily records
• Some events, such as illness, lifestyles, stress or travel, may make fertility indicators harder to interpret
• You need to avoid sex or use male or female condoms during the fertile time
• Natural methods don't protect you against sexually transmitted infections (STIs)

Can Anyone Use Natural Family Planning?

Most women can use natural methods as long as they receive good instructions and support. They can be used at all stages of your reproductive life, whatever age you are.

It will however take longer to recognise your fertility indicators and to start to use natural family planning if you have irregular cycles. Natural family planning is not a suitable method for women who do not have periods.

Recording the Temperature Fertility Indicator

Your body temperature changes through the menstrual cycle under the influence of oestrogen and progesterone. Temperature rises slightly after you have ovulated. You can chart these changes by recording your temperature each day to show you when the fertile time ends. You should use a special fertility thermometer or digital thermometer, which will show the small changes in temperature more easily.

Temperature should be taken under the tongue. Ear or forehead thermometers are not accurate enough to use. You need to take your temperature before you get out of bed or after you have had at least 3 hours rest. This is known as your basal body temperature (BBT) or waking temperature. This should be done at the same time each day and before you have anything to eat or drink. The fertile time ends when you have recorded temperatures for 3 days in a row, which are higher than all the previous 6 days.

The difference in temperature will only be about 0.2 degrees Centigrade (0.4 degrees Fahrenheit). Certain activities or events can alter your temperature readings and can make them less accurate. For example if you have an illness, such as a cold or flu, drink alcohol or oversleep (this can make your temperature go up). Also painkilling drugs, including aspirin, can make your temperature go down.

The Cervical Secretions Fertility Indicator

The amount of oestrogen and progesterone varies in the menstrual cycle and alters the quantity and consistency of cervical mucus. By monitoring the changes in your cervical secretions you can learn to identify the start and end of your fertile time.

After your period you may notice a few days when your vagina and vulva area feels dry and you can’t see or feel any cervical secretions. As the level of oestrogen rises, your body prepares for ovulation, the secretions produced by the cervix begin to change in texture and increase in amount. At first, they feel moist, sticky and appear white or creamy in colour. This is the start of the fertile time. Just before ovulation the secretions become clearer, wetter, stretchy and slippery like raw egg white. This is known as fertile mucus and is a sign that you are at your most fertile. After ovulation the cervical secretions return to being thicker and sticky and after 3 days you will no longer be fertile.

Combining the temperature and cervical secretions indicators acts as a double check and increases the effectiveness of natural family planning. The fertile time starts at the first sign of any cervical secretions. It ends after the third high temperature has been recorded and all three high temperatures occur after the last day of having wetness or clear, slippery secretions (the peak day).

Fertility Monitoring Devices

You can buy a number of different fertility devices. They work by monitoring changes in temperature, urine or saliva. In the UK the main product available is Persona. This consists of a small handheld computerised monitor and a series of urine test sticks, which measure hormonal changes. Persona interprets these changes and can predict the fertile and infertile times of your menstrual cycle. If you use Persona according to the instructions, it is around 94% effective. This means that at least 6 women in 100 will get pregnant in a year.

Computerised thermometers such as Bioself, LadyComp/BabyComp and Cyclotest work by combining information about the length of your menstrual cycle and temperature. More research is needed about the effectiveness of these products.

Luteinising hormone (LH) dipstick tests, or ovulation predictor kits, are designed to be used by women planning a pregnancy. They are not effective as a natural family planning method.

Breastfeeding as a Natural Family Planning Method

Breastfeeding can be very effective in avoiding pregnancy. It is known as the lactational amenorrhoea method (LAM). Breastfeeding can be up to 98% effective in avoiding pregnancy. It is however only effective when:

• Your baby is less than 6 months old
• You are fully breastfeeding and are not giving your baby any other liquid or solid food
• You are not having periods

If not, an additional form of contraception, such as condoms, the IUCD or the POP, is required.