Natural family planning is an effective method of avoiding pregnancy provided you are well-motivated and properly taught. This leaflet does not tell you how to practise natural family planning. It gives basic background information on how it works. You need detailed instruction explaining how to do natural family planning. See the organisations listed at the end of the leaflet.
What is natural family planning?
Natural family planning is a method of preventing pregnancy, without using pills or devices. It is based on 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. It can be a very effective form of contraception. However, it needs a 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.
How effective is natural family planning?
If natural family planning is used correctly by 100 women for one year, somewhere between one and nine women would become pregnant. This compares to 80 or 90 women who would become pregnant using no method of contraception. This method will be less effective if not used correctly.
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 is 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.
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 natural family planning. 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'. These 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). However, if you take your temperature before getting out of bed each morning, a pattern usually emerges. This will show you when ovulation has occurred. Computerised thermometers are also available which work by combining information about the length of your menstrual cycle and temperature.
- 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.
- 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. These are devices that you can buy 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 may be helpful in planning pregnancy.
Is breast-feeding a natural family planning method?
Yes - this is known as the lactational amenorrhoea method of contraception. Lactational means while you are breast-feeding, and amenorrhoea means not having any periods. Suckling by the baby stimulates hormones that suppress ovulation. Ovulation is unlikely for six months after childbirth if you breast-feed fully (this means the baby has no other food or drink apart from breast milk) and if you have not had a period since childbirth.
Less than one woman in one hundred would become pregnant in these circumstances. However, once you drop feeds, or start having periods this would not be an effective method of contraception.
How do I learn to do natural family planning?
If you want to consider natural family planning then contact the organisations shown below for further information.
Further help & information
Dr Tim Kenny
Dr Mary Harding
Dr Helen Huins