Natural Family Planning

What is natural family planning?

Natural family planning is a method of birth control. With this method, you do not have sex during the days of your menstrual cycle when you are more likely to get pregnant (your fertile days). It is also called the rhythm method, fertility awareness, or periodic abstinence.

Normally during each menstrual cycle one of your ovaries releases an egg. This is called ovulation. The egg travels through the fallopian tube to the uterus. Pregnancy happens if the egg is fertilized by sperm. Sperm can live inside your body for 3 days or longer after you have sex. This means that you can get pregnant up to 3 days or more after you have sex if you ovulate during that time.

The length of the menstrual cycle varies from woman to woman. It can also vary month to month. An average menstrual cycle lasts 26 to 32 days. However, some women normally have regular cycles as short as 21 days or long as 35 days. Usually your menstrual periods are more regular when you are 20 to 40 years old. For this reason, natural family planning works best if you are in this age group.

How can I know when I’m fertile?

Natural family planning depends on accurately tracking your menstrual cycle to know which days are safe for sex. There are several ways to do this. Symptoms like pain in the area of the ovaries, low back pain, breast tenderness, and bloating can help you know which days you are fertile.

You can also buy ovulation kits in a pharmacy without a prescription. The kits can tell you exactly when you ovulate. They are simple to use. You put a sample of your urine on the test strip. The test strip will change color if you are ovulating.

Other methods to figure out your fertile days are:

  • Basal body temperature method
  • Cervical mucus or ovulation method
  • Symptothermal method
  • Calendar method
  • Standard days method

How do I use the basal body temperature method?

Basal body temperature (BBT) is your temperature when you wake up in the morning. Your BBT is a little higher when you ovulate, but it can be hard to get good BBT readings. If you record your BBT every day for several months, you can learn which days are likely to be your fertile days. You will need to use a special, basal body thermometer, which you can buy at the drugstore. It lets you measure very small changes in your oral or rectal temperature. Take your temperature right after you wake up. Do it before you get out of bed, eat, drink, smoke, or have sex. Just after you ovulate your temperature will be about 0.5 to 1°F (0.5°C) higher. It will stay higher until your next period starts. If you do not want to get pregnant, you should not have sex from the time your period ends until 3 days after your temperature rises. For most women, this time to avoid sex will last for about 2 weeks. Write down your BBT every day on a calendar.

When you use this method of birth control it is important to remember that illness, drugs, and alcohol can raise your body temperature.

How do I use the cervical mucus or ovulation method?

Cervical mucus is a jellylike vaginal discharge that comes from the cervix. The cervix is the opening of the uterus into the vagina. The mucus is thick and sticky during most days of the menstrual cycle. It usually gets clear, thin, and watery (like uncooked egg white) about 4 days before ovulation.

You can check the cervical mucus with your finger or a piece of toilet paper. Days when the mucus is clear, thin, and watery are called wet days. If you do not want to get pregnant, you should not have sex from the time the watery mucus appears until 4 days after the mucus gets thick, sticky, and smaller in amount. Be careful that you don’t confuse wet-day mucus with semen that leaves your vagina after sex.

How do I use the symptothermal method?

The symptothermal method uses a combination of the basal body temperature and cervical mucus methods to know when you could get pregnant. You will need to check your temperature and cervical mucus every morning. Combining the 2 methods may slightly improve your ability to predict ovulation.

How do I use the calendar method?

The calendar method is also called menstrual charting. You must keep track of how many days each menstrual cycle is. Count the days from the first day of one period to the first day of your next period. Do this for 8 cycles. Then you can figure out the days that you are most likely to get pregnant: Subtract 18 days from the number of days of your shortest cycle, and subtract 11 days from the number of days of your longest cycle. Use this range of days to know when your fertile days are most likely to happen. For example, if the shortest number of days in your menstrual cycle is 28 days, 28 – 18 = 10. If the longest number of days in your menstrual cycle is 32 days, 32 – 11 = 21. This would mean that you are most likely time to get pregnant between 10 and 21 days after you start having your period each month. If you do not want to get pregnant, you should not have sex during this time.

How do I use the standard days method?

On a calendar, mark and circle the day when your period first begins as Day 1. Then mark and circle the same day of the week, 1 week later, as Day 8. Count forward to Day 19 and circle it. Draw a solid line through days 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and 19. Days 8 through day 19 are days when you are more likely to get pregnant. For these 12 days (days 8 through 19), do not have sex if you want to avoid getting pregnant.

All other days in each cycle have a low risk of pregnancy. You can have sex on days 1 through 7 and on day 20 and the days after that until your next period starts. Mark the day your next period starts as Day 1 of the next cycle. Then go back to the previous cycle on the calendar and count the total number of days in the previous cycle. Put a square around the total number of days for that cycle and do the same thing for each following cycle. If a cycle was 30 days long, the last day will be marked 30. Keep these calendar pages, so that you have a record of how long each cycle was.

This method works if no more than 1 cycle per year is less than 26 days long or more than 32 days long. If more than 1 cycle per year was shorter than 26 days or longer than 32 days, use a different method of natural family planning.

Does breast-feeding prevent pregnancy?

Frequent breast-feeding can prevent ovulation and keep you from having menstrual periods. You must breast-feed at least 8 to 10 times per day, with no more than 6 hours between feedings, if you do not want to get pregnant. Do not use this as a method of birth control if you are not breastfeeding this often. You should also not use it if you are feeding your baby other foods or formula or if you start having menstrual periods again.

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?

  • You should not try this form of birth control until you and your partner learn more about it. You and your partner should be comfortable with your choice of a natural family planning method before you use it as your only method of birth control. You should avoid having sex, or use diaphragms, condoms, and spermicides, until you have figured out when your fertile days are and when it is safe to have sex. You can’t figure out your fertile days if you take hormones, such as birth control pills, because they interfere with your normal cycle.
  • If you do not follow the instructions completely, or if you have irregular menstrual periods, natural family planning is less reliable than other forms of birth control. If it is not practiced carefully, 2 to 3 of every 10 women get pregnant during 1 year of use.
  • There are days every month when you should not have sex.
  • It requires time, energy, commitment, and careful record-keeping.
  • It does not protect against sexually transmitted diseases, including HIV/AIDS.
Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth.
Last modified: 2014-12-11
Last reviewed: 2014-12-11
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 ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.

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