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Natural family planning (NFP)

Information on how natural family planning can help you to avoid pregnancy.

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

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:

  • 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.

The menstrual cycle is controlled by your body’s natural hormones – estrogen and progesterone.

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. You can also use fertility monitoring devices (see How do I use fertility monitoring devices?).

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. Occasionally, more than 1 egg is released (within 24 hours of the first egg being released) 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?

How effective any contraceptive method is depends on how old you are, how often you have sex and whether you follow the instructions.

If 100 sexually active women don't use any contraception, 80 to 90 will become pregnant in a year.

If used according to teaching and instructions, 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.

Natural family planning is more effective when taught by a specialist natural family planning teacher, and when more than one fertility indicator is used.

Some people choose to combine their fertility awareness knowledge with male or female condoms – this is sometimes known as fertility awareness combined methods. The effectiveness of this depends on how well you use male or female condoms.

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 can help you recognise normal and abnormal vaginal secretions

  • It can help you to communicate about your fertility and sexuality

  • 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. Natural family planning may not be a suitable method for some women who do not have periods.

It may take longer to recognise your fertility indicators and to start to use natural family planning if you have irregular cycles, or at certain times, for example after stopping hormonal contraception, after having a baby, during breastfeeding, after an abortion or miscarriage, or when approaching the menopause.

How do I record the fertility indicators?

Some natural methods rely on using only 1 of the fertility indicators. Other methods use 2 or more indicators, which is more effective.

How do I record the temperature fertility indicator?

Your body temperature changes through the menstrual cycle under the influence of estrogen and progesterone – it 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. Visit to download a fertility chart. You should use a special mercury fertility thermometer or digital thermometer which will show the small changes in temperature more easily. Ear or forehead thermometers are not accurate enough to use.

Do I need to take my temperature at a particular time?

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 be about 0.2 degrees Centigrade (0.4 degrees Fahrenheit).

Can anything alter the temperature readings?

Certain activities or events can alter your temperature readings and can make them less accurate. For example if you:

  • Take your temperature earlier or later than normal

  • Use poor equipment or record the findings badly

  • Have an illness, such as a cold or flu, drink alcohol or oversleep (this can make your temperature go up)

  • Are taking painkilling drugs, including aspirin (this can make your temperature go down).

The temperature indicator on its own does not help you to find the start of your fertile time.

How do I monitor the cervical secretions fertility indicator?

The amount of estrogen and progesterone varies in the menstrual cycle and this alters the quantity and type 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 estrogen rises, your body prepares for ovulation, the secretions produced by the cervix begin to change in texture and increase in amount and sensation. 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.

The amount and quality of cervical secretions will vary from woman to woman and also from one cycle to the next.

Can I combine temperature and cervical secretions fertility indicators?

Yes. 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 and 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).

How can I work out how long my menstrual cycle lasts?

The length of your cycles can help you to work out the start of your fertile time. Keep a record of the length of your last 6 cycles, then find your shortest cycle and subtract 20 days to find the first fertile day. However, calculating your cycle length is not a reliable way of working out the end of your fertile time and this should not be used on its own as a fertility indicator.

How do I monitor changes to my cervix?

During your menstrual cycle your cervix changes in position and feels different. Around your fertile time the cervix will feel higher in the vagina, soft and slightly open. During your infertile time your cervix will feel low in the vagina, firm to touch and closed. These changes are not reliable enough to be used on their own as a fertility indicator.

Are there any other fertility indicators?

Some women may be aware of pain around ovulation or changes in the breasts, skin, mood or sex drive. These are the least reliable indicators of your fertile time.

How do I use fertility monitoring devices?

You can buy a number of different fertility devices at pharmacies. 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.

Can I use breastfeeding as a natural family planning method?

Breastfeeding is also known as lactation. When used as a contraceptive method it can be very effective in avoiding pregnancy and is known as lactational amenorrhoea (LAM). LAM is only effective when:

  • Your baby is less than 6 months old

  • If you are fully breastfeeding – this means you are not giving your baby any other liquid or solid food

  • You are nearly fully breastfeeding – this means mainly breastfeeding your baby and infrequently giving your baby other liquids

  • You have no periods.

All of the above points must apply for breastfeeding to be an effective family planning method – if you follow the guidance carefully breastfeeding can be  up to 98% effective in avoiding pregnancy.

Are there any other natural family planning methods?

Two other natural family planning methods are being researched. These are called The Standard Days Method and The TwoDay Method. These are not in general use in the UK.

If I have to use hormonal emergency contraception will it affect my fertility indicators?

Yes. Using hormonal emergency contraception will upset your normal hormone pattern and alter your fertility indicators. After using hormonal emergency contraception you should not rely on your natural family planning indicators for 2 complete menstrual cycles. This allows time for your cycle to return to normal and for your natural family planning indicators to be reliable.

Where can I get help with natural family planning?

If you decide to use natural family planning you need to find someone to teach you how to use it. General practice and family planning clinics do not often teach natural family planning so you may need to find your own teacher. Some teachers charge a fee.

You can get further information or help to find your local teacher from:

How do I find out about contraception services?

Contraception is free for women and men of all ages through the National Health Service.

  • You can find out about all clinics from sexual health direct, run by fpa on 0845 310 1334 or visit the website

  • You can get lists of general practices from libraries, primary care trusts or health boards and some advice centres and helplines

  • You can get details of your nearest family planning or sexual health clinic from: local directories, health centre, hospital, midwife or health visitor, advice centre, NHS Direct on 0845 46 47 (NHS 24 in Scotland 0845 4 24 24 24), primary care trust or health board

  • Young people can also phone Brook on 0800 0185 023 or Sexwise on 0800 28 29 30 for details of the nearest young people’s clinic.

Emergency contraception

If you have had sex without using contraception or think your method might have failed there are two emergency methods you can use:

  • The emergency hormonal pill – must be taken up to 3 days (72 hours) after sex. It is more effective, the earlier it is taken after sex

  • An IUD – must be fitted up to 5 days after sex, or up to 5 days after the earliest time you could have released an egg (ovulation).

Ask your doctor or nurse about getting emergency pills in advance, just in case you need them.

Sexually transmitted infections

Most methods of contraception do not protect you from sexually transmitted infections.

Male and female condoms, when used correctly and consistently, can help protect against sexually transmitted infections. If you can you should avoid using condoms containing Nonoxinol 9 (spermicidally lubricated), as this does not protect against HIV and may even increase the risk of infection. If you are using condoms as part of fertility awareness you should not use additional spermicide at all as this will make it difficult to interpret your daily cervical secretions.

How fpa can help you

sexual health direct is a nationwide service run by fpa. It provides:

  • Confidential information and advice on contraception, sexually transmitted infections, planning a pregnancy, pregnancy choices and sexual wellbeing

  • Details of family planning clinics, sexual health clinics and other sexual health services

  • A wide range of leaflets on individual methods of contraception, common sexually transmitted infections, abortion and planning a pregnancy.

fpa helplines

helpline 0845 310 1334
9am to 6pm Monday to Friday

Northern Ireland
helpline 028 90 325 488 (Belfast) or
helpline 028 71 260 016 (Derry)
9am to 5pm Monday to Thursday, 9am to 4.30pm Friday

helpline 0141 576 5088
9am to 5pm Monday to Thursday, 9am to 4.30pm Friday

or visit fpa's website

A final word

This leaflet can only give you basic information about natural family planning and other methods of contraception. The information is based on the evidence and medical opinion available at the time this leaflet was printed. Different people may give you different advice on certain points. All methods of contraception come with a Patient Information Leaflet which provides detailed information about the method.

Remember – contact your doctor, practice nurse or a family planning clinic if you are worried or unsure about anything.

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