What is natural family planning?

Natural family planning is a term used for methods of birth control that do not involve the use of any drugs or devices. To prevent pregnancy, these methods require not having sexual intercourse during the fertile days of a woman's menstrual cycle. They depend on accurately recording information about a woman's menstrual cycle and calculating safe or unsafe days for intercourse. Natural family planning requires strong commitment, cooperation, and motivation from both partners.

What are the methods of natural family planning?

The calendar method, a way of mathematically calculating your fertile days based on your longest and shortest menstrual cycles, is no longer recommended as a method of contraception because it is highly unreliable.

The most reliable method of natural family planning is the symptothermal method (also called the mucothermal method). It is a combination of two methods: the temperature method and the cervical-mucus method. If you want to use the symptothermal method of birth control, you must observe the appearance of your cervical mucus and record your daily morning temperature. You will use this information to determine the days when you are fertile. You should not have sex during these fertile days if you don't want to get pregnant. When you use this method, you will find that you should not have sex about 8 to 11 days every month.

When is a woman fertile?

A menstrual cycle is approximately 28 days long. Normally during each menstrual cycle an egg is released from one of the two ovaries. The release of an egg is called ovulation. The egg travels through a fallopian tube to the uterus. If the egg is not fertilized after it leaves the ovary, it is absorbed by the body or shed during menstruation. The egg can be fertilized by sperm from the moment it is released by the ovary until it has passed through the outer one third of a fallopian tube. It is during this time that a woman is fertile and must avoid sex if she does not want to get pregnant. The symptothermal method of birth control is based on calculating when these fertile days will occur and avoiding sex during these days.

How do I follow my temperature?

You must measure your basal body temperature every morning before any physical activity, including smoking, drinking, or eating. It is best to do it while you are still in bed. You need to use a special basal body thermometer that can detect small changes in temperature. You can buy one of these thermometers at a drug store. Your body temperature will rise about 0.5 to 1 degree F (0.5 degree C) just after ovulation. It will stay elevated until your next period starts. Write down your temperature every day on a calendar.

How does the cervical mucus change?

You should also check the appearance and consistency of the mucus in the cervix (opening to the uterus). When the mucus appears thin, elastic, clear, and watery (like egg white), ovulation will occur within 4 days (these are called wet days). You should avoid intercourse from the time the wet mucus appears until 4 days after the mucus becomes drier, thicker in consistency, and smaller in amount.

How is the symptothermal method used?

Observing both your temperature and cervical mucus will help you pinpoint the time of ovulation. Once you have learned how your body temperature and cervical mucus change during each menstrual cycle, you can estimate when you will be fertile each month. As a rule you can have sex from day 1 of your cycle (the day your menstrual bleeding starts) until you first notice 'wet' mucus. Do not have sex again until you observe 4 days of thick, dry mucus or until your temperature has been up for 3 full days.

It is important to avoid sex as soon as you observe wet-day mucus because the average lifespan for sperm is 3 days. This means a sperm can live inside your body for 3 days and cause a pregnancy when you ovulate.

When you use this method of birth control it is important to remember that illness and any drugs, including alcohol, can raise your body temperature. Also be careful that you don't confuse 'wet day' mucus with semen.

To increase the effectiveness of this method, avoid having sex or use another method of birth control during the first half of your menstrual cycle until your basal body temperature has risen and remained up for 3 days.

The length of the menstrual cycle varies from woman to woman and can vary from month to month. You should carefully observe and record your body temperature and cervical mucus for 3 to 6 months before you use natural family planning as your only method of birth control. If you want to have sexual intercourse during this 3- to 6-month period, use condoms or a diaphragm; these methods of birth control will not affect your measurements. If you have very irregular periods you should not use natural family planning to prevent pregnancy.

What are the benefits?

The advantages of natural family planning are:

• ability to have some control over when you have children without using drugs or devices

• enjoyment of sex without the interruption or discomfort of barrier methods of birth control

• avoidance of the health risks associated with methods such as birth control pills and the IUD

• low cost.

What are the disadvantages?

Natural family planning has a variety of disadvantages, which include:

• 20% to 30% failure rate (2 to 3 of every 10 women get pregnant during 1 year of use)

• not having intercourse during the 3 to 6 months of initial observation of the menstrual cycle

• not having intercourse for up to 2 weeks every month

• unsuitability for women who have irregular periods

• difficulty in avoiding fertile periods

• no protection against sexually transmitted diseases, including AIDS.