Fertility awareness (also called natural family planning or periodic abstinence) involves monitoring the many changes your body goes through during a menstrual cycle. This information can help you identify when you ovulate and can be used to time sexual intercourse either to avoid getting pregnant or to increase your chances of becoming pregnant.

A woman is usually able to get pregnant for about 5 days each month, when ovulation occurs. On average, ovulation occurs 12 to 16 days before the menstrual period begins. Therefore, ovulation would occur on about day 10 of a 24-day menstrual cycle, day 14 of a 28-day cycle, or day 21 of a 35-day cycle. The key to becoming pregnant or to avoiding pregnancy is determining when ovulation will occur. Because sperm can live for 3 to 5 days in a woman's reproductive tract, it is possible to become pregnant if intercourse occurs several days before ovulation.

See an illustration of the menstrual cycle.

For fertility awareness to be an effective method of contraception, you must abstain from sex or use a barrier method of contraception (such as a diaphragm or condom) for 8 to 16 days of every menstrual cycle. This method of birth control requires significant forethought and preparation, close observation of your body changes, and cooperation between you and your partner.

There are several basic methods for determining the time of ovulation. For fertility awareness to be most effective, you need to use all of these methods in combination.

• Calendar (rhythm) method. For the calendar method, you estimate ovulation based on a record of your previous menstrual cycles. From the record, you predict which days of the month you are most fertile. Your fertile days start 5 days before ovulation. This method assumes that your cycle is regular and that you will ovulate on a certain day of the month. However, very few women actually have regular 28-day cycles, and even those who do can have irregular periods from time to time. Also, a woman does not always ovulate right in the middle of her cycle. The best estimate is that ovulation occurs between 9 and 17 days before the next period. Therefore, use of the calendar method alone is not recommended as a method of birth control.
• Basal body temperature (BBT) method. Basal body temperature (BBT) is the lowest body temperature a healthy person achieves during a day. Because of the natural changes that occur in a woman's hormone levels during her menstrual cycle, her BBT falls 1 to 2 days before ovulation and rises 1 to 2 days after ovulation. By carefully measuring and charting your BBT every morning before you get out of bed, you may be able to estimate the time of ovulation.
• Cervical mucus method (Billings method). The amount, texture, and appearance of mucus produced by your cervix changes during your menstrual cycle. By observing, feeling, and recording the nature of the mucus over several cycles, you may be able to predict when ovulation occurs.
  Prev Page12 3 4 5 6 7 Next Page