Natural family planning is a method of preventing pregnancy that does not involve medicines or devices. The fertility awareness method is a type of natural family planning that involves being able to predict your fertile time. This is the time you are likely to conceive.
Natural family planning can be an effective method of avoiding pregnancy but you have to be very well motivated and properly taught.
This leaflet does not tell you how to practise natural family planning or any of the fertility awareness methods. It gives basic background information on how they work. You need detailed instruction from an expert for fertility awareness methods to be most effective. There are links at the end of this leaflet explaining where to obtain this expert advice in the UK.
What is natural family planning?
Methods of natural family planning are any method of preventing pregnancy that does not involve taking a contraceptive medicine or using a contraceptive device:
- Withdrawal method (coitus interruptus) - relies on the man being able to tell when he is near climax and pulling out of his partner's vagina before ejaculation; also called the pullout method:
- Requires immense self-control on the man's part.
- Although widely practised, this method is not recommended as a form of contraception, due to the number of unplanned pregnancies it leads to.
- Fertility awareness method (FAM) - relies on by being able to predict your fertile time. This is the time you are likely to conceive. Pregnancy is avoided if you don't have sex during this fertile time or use other methods of contraception, such as condoms. FAM may be:
- A combination of all three of the above is the most reliable method of identifying the fertile time.
- Lactational amenorrhoea method (LAM) - relies on the contraceptive effects of breastfeeding fully:
- Lactational means while you are breastfeeding, and amenorrhoea means not having any periods.
- Less than 2 women in every 100 doing this for the first six months after their baby is born will become pregnant. After this time or if feeds are missed, it becomes less effective.
- You can read more about this in the separate leaflet called Contraception after Having a Baby.
Note: none of the natural family planning methods protects against sexually transmitted infections.
The rest of this leaflet is about the fertility awareness based method of natural family planning. It can be a very effective form of contraception. However, it needs a very high level of commitment from both you and your partner. It has the advantage that there are no chemicals involved, and therefore no side-effects. It has the disadvantage of not having any of the benefits of hormonal contraception.
Some women also use a fertility awareness based method to help them plan a pregnancy.
Effectiveness of the fertility awareness method
The effectiveness of natural family planning, in particular the FAM, depends on how reliably it is used. If it is used correctly by 100 women for one year, somewhere between one and nine women would become pregnant. This compares to 80-90 women who would become pregnant using no method of contraception. This method is less effective if not used correctly: about 24 women will become pregnant if you include women who have not had any teaching on how to use the method.
Natural family planning may be a useful form of contraception as you get older and become naturally less fertile. However, it is difficult to use this method if your periods are irregular. There is more information on contraception for the older woman in the separate leaflet called Contraception for the Mature Woman.
In one recent study using a fertility awareness method app, more than half of the women who had originally enrolled were no longer using the app after one year. This could be because, even when using an app to help, using an FAM for contraception is more complicated and time-consuming than other methods of contraception.
If you are using a natural family planning method of any kind, you may worry that you might have risked becoming pregnant. Please see our separate leaflet called Emergency Contraception for information about your options.
When is the fertile time?
The fertile time lasts for approximately 8-9 days in each cycle. It is from seven days before ovulation until 1-2 days after ovulation. Ovulation occurs when a woman releases an egg from an ovary - usually once a month. An egg survives for about 24 hours. However, sperm can survive for up to seven days after sex. This is why the fertile time starts from seven days before ovulation. So, if you know exactly when you will ovulate then you can predict when your fertile days are. This also means that for around nine days in every period cycle you will have avoid having sex or use a barrier method of contraception.
How do I know when I will ovulate?
Knowing when you ovulate is the key to this method. Once you are confident that you can predict this then this method of family planning can be very effective. It takes good instruction and 3-6 menstrual cycles to learn how to do the fertility awareness method. This is much more difficult to do if you have irregular periods.
You need to make a record each day of one or more 'indicators'. In the past the only way of recording these was on a natural family planning chart or in a natural family planning book. However, there are now many smartphone apps (usually described as either a fertility awareness method app or a natural family planning app) that are based on using these signs to identify the safe days.
Note: many apps are simply a way to track your periods and are not designed to be used as part of a fertility awareness based method of contraception.
The 'indicators' include the following:
- Body temperature. This typically rises slightly when you ovulate and remains higher until your next period:
- There are many factors that can upset this, such as illness and taking medicines (like paracetamol, which can lower your temperature).
- If you take your temperature before getting out of bed each morning (basal body temperature), a pattern usually emerges. This will show you when ovulation has occurred.
- The pattern or rhythm that emerges is why this method is sometimes called the rhythm method.
- Computerised thermometers are available which work by combining information about the length of your menstrual cycle and temperature. Some of these also link to a mobile fertility app.
- Recent research suggests that a device worn on the wrist that measures your skin temperature may offer an alternative to taking your temperature with a conventional thermometer.
- Secretions from the neck of the womb (cervix). These change throughout the menstrual cycle:
- Just after a period there is not much secretion and the vagina is dry for a few days.
- About eight days before ovulation, the secretions become more moist, sticky and cloudy.
- Four days before ovulation the secretions become wet, clear, slippery and stretchy (like egg white).
- A day or so after ovulation the secretions dry up again until after the next period.
- So by observing the changes in your secretions you can predict the 7-8 days before ovulation.
- Cycle length. Ovulation usually occurs 12-16 days before a period. If your cycle is very regular then this may help to predict ovulation.
- Ovulation prediction kits (OPKs). These are devices that you can buy, usually from a pharmacy. There are two types of ovulation prediction kits. They both measure hormone levels. One measures them in your urine and the other measures them in your saliva:
- The urine-based kit detects the increase, or surge, of a hormone called luteinising hormone (LH) that occurs approximately one to two days before ovulation. The main device available in the UK is called Persona®. Although a small amount of LH is always present in your blood and urine, in the days before ovulation, the amount increases by about two to five times.
- Saliva-based kits test for rising oestrogen levels as you near ovulation. As oestrogen levels rise, the salt content of your saliva increases too and when the salt dries it crystallises into a fern-like pattern. With these kits, you see if 'salivary ferning' has occurred as your saliva has dried. The saliva-based kits are less accurate than the urine-based kits. These are not advised for avoiding pregnancy but they may be helpful in planning pregnancy.
How do I learn to do a fertility awareness method?
If you want to consider a fertility awareness method then it is advisable to have training from an expert. You can access natural family planning classes and individual teaching in the UK via organisations such as your local family planning clinic, Fertility UK or Brook.
Further reading and references
Fertility Awareness Methods; Faculty of Sexual and Reproductive Healthcare (June 2015 - updated November 2015)
Freundl G, Sivin I, Batar I; State-of-the-art of non-hormonal methods of contraception: IV. Natural family Eur J Contracept Reprod Health Care. 2010 Apr15(2):113-23.
Trussell J; Contraceptive failure in the United States, Contraception, 2011
Berglund Scherwitzl E, Lundberg O, Kopp Kallner H, et al; Perfect-use and typical-use Pearl Index of a contraceptive mobile app. Contraception. 2017 Dec96(6):420-425. doi: 10.1016/j.contraception.2017.08.014. Epub 2017 Sep 4.
Shilaih M, Goodale BM, Falco L, et al; Modern fertility awareness methods: Wrist wearables capture the changes of temperature associated with the menstrual cycle. Biosci Rep. 2017 Nov 24. pii: BSR20171279. doi: 10.1042/BSR20171279.