Natural Family Planning Methods

Natural family planning contraceptive methods include those that do not require medication, physical devices, or surgery to prevent pregnancy.

Cycle-based fertility awareness methods rely on tracking the changes in the body that signal fertility. A woman is only fertile during part of the menstrual cycle. By monitoring certain changes in her body, a woman can more or less predict the fertile phase and abstain at that time. She can also use barrier methods if she isn't prohibited by religious beliefs. The Catholic Church, for example, generally approves most natural family planning methods.

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Monitoring Basal Body Temperature. To determine the most likely time of ovulation and therefore the time of fertility, a woman is instructed to take her body temperature, called her basal body temperature. This is the body's temperature as it rises and falls in accord with hormonal fluctuations.

• Each morning before rising, the woman takes her temperature with a specialized basal body thermometer and marks the result on a graph-paper chart. (Of interest is a wrist watch-like device under investigation that measures skin changes to predict ovulation.)
• The woman also notes the days of menstruation and sexual activity.
• The so-called "fertile window" is six days long and starts five days before ovulation and ends the day of ovulation.
• The chances for fertility are considered to be highest between days 10 and 17 in the menstrual cycle (with day 1 being the first day of the period and ovulation occurring about two weeks later). It should be noted, however, that a 2000 study reported that only 30% of women were fertile within that period of time. In the study, women had a 10% chance of ovulating on each day between day 6 and 21. Researchers who conducted the study suggested that each woman track the length of her cycle, which in the general population of women actually runs between 19 and 60 days. A long cycle, for example, suggests a delayed ovulation date.
• Immediately after ovulation, the body temperature increases sharply in about 80% of cases. (Some women can be ovulating normally yet not show this temperature pattern.)