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Fertility Awareness

Why It Is Done

Fertility awareness is done to help a woman learn when she is likely to ovulate. This information can help a woman:

  • Become pregnant. Pregnancy is most likely to occur when sexual intercourse occurs close to the time of ovulation.
  • Avoid pregnancy. A couple may use fertility awareness for birth control if:
    • Their religious beliefs do not allow the use of other methods of birth control.
    • They wish to use a "natural" method of birth control that does not use medicines, surgery, or other devices.
    • They are willing to pay close attention to the woman's cycle.
    • They are willing to not have sex or to use another birth control method during fertile days.
    • Preventing a sexually transmitted infection (STI) is not a concern.

To use fertility awareness as a birth control method:

  • The woman should have regular menstrual cycles.
  • The woman must watch her body for changes during her menstrual cycle. She must keep good records of her cycles.
  • Both partners must do this method together. The couple must be willing to not have sex or to use a barrier contraceptive on days when the woman is fertile.
  • The couple must be willing to have an unplanned pregnancy if this is their only method of birth control.

How To Prepare

Before you use fertility awareness as a method of birth control, record three or four of your menstrual cycles to find your pattern of ovulation. If you are trying to not become pregnant during this time, use a method of birth control that does not affect ovulation (such as a condom, diaphragm, or the copper intrauterine device [IUD]) or do not have sex.

Basal body temperature is checked using a special oral thermometer marked in fractions of a degree so you can see even small changes in temperature better than with an ordinary thermometer. Easy-to-read digital thermometers can be found in most pharmacies or at family planning clinics. Do not use a digital ear thermometer for this method.

How It Is Done

For fertility awareness to work well, it is best to use all of the following methods together.

Calendar (rhythm) method

Record 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 18 away (subtract) from the number of days in your shortest menstrual cycle. Your first fertile day should be that many days after your menstrual bleeding begins. 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.

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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