How It Is Done
For fertility awareness to work well, it's best to use all of the following methods together.
Calendar (rhythm) method
Write down the dates of your menstrual periods for 6 to 8 months. See if your menstrual cycle is regular and how many days it is. If your cycle is regular and about 28 days long, you are most likely to ovulate 14 to 15 days after menstrual bleeding begins.
To find the first day that you are likely to be fertile, take away (subtract) 18 from the number of days in your shortest menstrual cycle. Your first fertile day should be that many days after your menstrual bleeding starts. For example, if your shortest menstrual cycle is 26 days long, you would subtract 18 from 26 to get 8. Your first fertile day would then be the 8th day after menstrual bleeding begins.
To find the last day that you are likely to be fertile, subtract 11 from the number of days in your longest menstrual cycle. Your last fertile day should be that many days after your menstrual bleeding starts. For example, if your longest menstrual cycle lasts 31 days, you would subtract 11 from 31 to get 20. Your last fertile day would then be the 20th day after menstrual bleeding begins.
Sperm can live in your vagina 3 to 5 days after sex.
- If you want to get pregnant, have sex every day or every other day from your first fertile day to your last fertile day.
- If you do not want to get pregnant, do not have sex—or be sure to use another method of birth control—for 1 week before your first fertile day. In the example above, your fertile period is from day 8 to day 20, so protect yourself from becoming pregnant for these 12 days of your cycle.
The calendar method of birth control isn't the best choice for women who have short, long, or irregular menstrual cycles.
Standard days method (SDM)
On the first day of your period, move the ring to the day 1 bead on the CycleBeads. Count each day as one bead. On days 1 to 7, you can have unprotected sex. On days 8 to 19, do not have sex, or be sure to use another method of birth control to avoid pregnancy. From day 20 to the end of your cycle, you can have unprotected sex. The days when you are likely to become pregnant or not likely to become pregnant will have different colored beads to help you track. This method works best for women who have cycles between 26 and 32 days long.
There are also computer and smartphone apps you can use to track your cycle.
Basal body temperature (BBT) method
Take your temperature every morning for several months just after you wake up. Do it before you eat, drink, or do any other activity. Use a special ovulation thermometer or digital thermometer that shows tenths (0.1) of a degree. You can take your temperature orally or rectally. Be sure to use the same location and the same thermometer each time. Leave the thermometer in place for a full 5 minutes. Write down your temperature. Then clean the thermometer and put it away. Any activity can change your basal temperature. Record your temperature on a chart or graph. Use a tracking chart with either Fahrenheit temperatures or Celsius temperatures to keep track of your temperature. Ovulation usually causes your BBT to rise by 0.4°F (0.2°C) and to stay high for over a week.
If you want to become pregnant, have sex every day or every other day from your first fertile day until 3 days after your BBT rises.
If you do not want to become pregnant, do not have sex—or be sure to use another method of birth control—from the end of your menstrual period until 3 days after you ovulate. After your temperature rises and stays high for 3 full days, your fertile days will be over. Your temperature on these 3 days should stay higher than on any of the other days in that cycle.
Cervical mucus method (Billings method)
Each day, put one finger into your vagina and write down the amount and color of the mucus, and how thick or thin it is. Test the "stretchiness" of the mucus by putting a drop of it between your finger and thumb. Spread your finger and thumb apart and see if the mucus stretches.
After your period, you will not have much cervical mucus. It will be thick, cloudy, and sticky. Just before and during ovulation, you will have more cervical mucus. It will be thin, clear, and stringy. It may stretch about 1 in. (2.5 cm) before it breaks.
If you want to get pregnant, have sex every day or every other day from the day you see your cervical mucus becoming clear and stretchable until the day it becomes cloudy and sticky. Do not test your mucus right after sex. Semen may be mixed with it.
If you do not want to get pregnant, do not have sex—or be sure to use another method of birth control—from the day your cervical mucus becomes clear and stringy until the 4th day after it becomes cloudy and sticky.
Another 2-day method of checking your cervical secretions can be done. Every day of your cycle, ask yourself these two questions: Did I have secretions today? Did I have secretions yesterday? For all days that you answer "yes" to one of these questions, it is likely that you are fertile. You can get pregnant if you have unprotected sex. If you answer "no" to both questions on any day, you are not likely to get pregnant.
Hormone monitoring
If you are using a home ovulation kit, follow the instructions on the kit exactly.
Combined (symptothermal) method
This method uses some of the other methods all at once to tell you the most fertile days of your cycle. You check your basal body temperature, the changes in your cervical mucus, and a hormone test. You watch for signs of ovulation (such as breast tenderness, belly pain, and mood changes). You may have any of the following physical signs of ovulation:
- Breast pain
- An increase in sexual desire
- Pain in your lower belly on one side or the other. This pain is called mittelschmerz. It can be sharp or dull and can last from a few minutes to a few hours. It occurs when the egg is released from the ovary on that side. The ovaries usually switch releasing an egg each cycle. The pain occurs on the side the egg is released from during that cycle.
If you do not want to become pregnant, do not have sex—or be sure to use another method of birth control—for 5 days before ovulation may occur and on the day of ovulation.
