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Natural Family Planning

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 sex 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 days for intercourse. Natural family planning requires strong commitment from both partners.

The most reliable methods of natural family planning are the ovulation and symptothermal methods. To use the ovulation method of birth control, the woman checks and records her cervical mucus every morning. Cervical mucus is a jellylike vaginal discharge that comes from the cervix. The cervix is the opening of the uterus into the vagina. For the symptothermal method, the woman checks and records her temperature and cervical mucus every morning. Other changes, such as pain in the area of the ovaries, low backache, breast tenderness, and bloating may be noted as well. You use this information to know which days you are fertile. You should not have sex during these fertile days if you do not want to get pregnant.

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 your ovaries. The release of an egg is called ovulation. The egg travels through a fallopian tube to the uterus. The egg can be fertilized by sperm as it travels to the uterus. If the egg is not fertilized after it leaves the ovary, it is absorbed by the body or shed during the monthly period. It is during this time that a woman is fertile and must avoid sex if she does not want to get pregnant. The methods of birth control described here are based on calculating when these fertile days will occur and avoiding sex during these days.

How does the cervical mucus change?

The cervical mucus looks and feels different around the time of ovulation. You can check the cervical mucus with your finger or a piece of toilet paper. When the mucus is thin, elastic, clear, and watery (like uncooked egg white), ovulation will occur within 4 days. These days are called wet days. You should avoid intercourse from the time the wet mucus appears until 4 days after the mucus becomes thick, sticky, and smaller in amount. It may then look white or yellowish instead of clear and watery.

How do I follow my temperature?

Your basal body temperature should be measured every morning before any physical activity. This includes drinking, eating, and smoking. It is best to do it while you are still in bed. You need to use a basal body thermometer. This type of thermometer can detect small changes in temperature. You can buy one at a drug store. Your body temperature will rise about 0.5 to 1F (0.5C) just after you ovulate. It will stay at this higher level until your next menstrual period starts. Write down your temperature every day on a calendar.

How do I use the symptothermal or ovulation methods?

Observing your temperature and cervical mucus will help you know when you have ovulated. As a rule, you can have sex from day 1 of your cycle (the day your menstrual bleeding starts) until you first notice a discharge of wet mucus. Do not have sex again until you observe 4 days of thick, dry mucus.

It is important to start avoiding sex as soon as you have wet-day mucus. The average lifespan for sperm is 3 days. This means a sperm can live inside your body for 3 days and cause a pregnancy if you ovulate during that time.

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 that leaves your vagina after intercourse.

The length of the menstrual cycle varies from woman to woman. It can also vary month to month. You should carefully 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 intercourse during this time, use condoms or a diaphragm. These methods of birth control will not affect your measurements.

It is now possible to buy ovulation kits, which can show you exactly when you ovulate.

How effective is natural family planning?

The ovulation and symptothermal methods of birth control can be 97 to 98% effective (2 to 3 pregnancies per 100 couples) when practiced correctly. However, if you do not follow the instructions completely, these methods will be much less effective, and they will be less reliable than some of the other forms of birth control.

What are the benefits?

The advantages of natural family planning are:

  • You can have some control over when you have children without using drugs or devices.
  • You can enjoy sex without the interruption or discomfort of barrier methods of birth control, such as condoms or diaphragms.
  • You can avoid the health risks of some methods such as birth control pills and the IUD.
  • It costs very little.

What are the disadvantages?

Natural family planning has several disadvantages, which include:

  • If it is not practiced carefully, the failure rate can be 20 to 30%. This means 2 to 3 of every 10 women get pregnant during 1 year of use.
  • There are days every month when you cannot have intercourse.
  • It requires time, energy, commitment, and careful record-keeping.
  • It does not protect against sexually transmitted diseases, including AIDS.

How can I learn more about natural family planning?

Classes are available for couples who choose to use natural family planning methods. This form of birth control should not be attempted until both partners have had the class and are comfortable with using this method.

For more information on family planning, contact your health care provider or the following organizations:

  • National Women's Health Information Center sponsored by the US Department of Health and Human Services at or call (800) 994-WOMAN
  • EngenderHealth, a nonprofit organization dedicated to making reproductive health care accessible to women and men around the world, at
Developed by Phyllis G. Cooper, RN, MN, and McKesson Provider Technologies.
Published by McKesson Provider Technologies.
Last modified: 2006-11-16
Last reviewed: 2006-09-22
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.
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