Natural Family Planning

September 17, 2011

Natural Family Planning planning is a method of understanding signs and patterns of fertility during the menstrual cycle to achieve or avoid pregnancy. Other terms for this method are fertility awareness method (FAM), the rhythm method, or periodic abstinence. The use of the term natural does not imply that other methods are “unnatural.” The expression actually means that the natural signs and symptoms of the menstrual cycle are observed,
recorded, and interpreted to ascertain when a woman is fertile. The couple then abstains or uses a barrier method or withdrawal during these times.

There are several methods that are considered to be natural family planning. All of these methods overestimate the time of fertility in order to compensate for the life span of the sperm and ova (egg). The sperm can live for 5 days within the female reproductive tract. The life span of the ova is 24 hr. The calendar method is the recording of the intermenstrual period (the number of days from the onset of one period to the onset of the next) for 6 months in order to ascertain the shortest and longest cycle length. The fertile time can then be determined by subtracting 18 from the shortest cycle length and 11 from the longest cycle. The couple then abstains from intercourse on the days corresponding to the fertile time. This would require periodic abstinence for an average of 16 days a cycle. The effectiveness rate of this method for perfect use is 3.1% for the first year. For imperfect use the failure rate is as high as 86.4%, however.

A second type of natural family planning is the basal body temperature (BBT) method. Fertility is determined by taking the temperature first thing in the morning before getting out of bed with a special thermometer for this purpose. The temperature is recorded. An increase of 0.2-0.4oF that continues for 3 days indicates that ovulation has occurred. The couple abstains or uses another method until after the ovulation temperature spike. Perfect use of this method has a failure of 2% and a typical use failure rate of 20%.

Another method of detecting fertility is observing the cervical mucus beginning the first day after menstruation stops. Just after menses, the vagina may feel moist for a few days. The mucus then becomes thicker and cloudy. As ovulation approaches, the mucus becomes more clear, slippery, stretchy, and abundant. The mucus may be stretched for 2-3 in. between the thumb and index finger during peak times. Ovulation occurs at the peak of this wetter, clearer mucus. The fertile time is the first day of peak mucus until 4 days after the peak day. Some issues that can make this method more difficult to interpret are the use of douching, having unprotected intercourse the day before since semen and arousal fluids can be confused with mucus, vaginal infections, and menstruation. Couples may either have intercourse only during the pre and post peak days or use another method during the peak times. Some choose to avoid having intercourse until after the peak each month. This method typically requires the help of a professional to correctly interpret the mucus findings.

The symptothermal method combines more than one indicator of fertility. Many use the temperature and mucus observations to determine fertile times. Other signs can also be used such as checking the position and consistency of the cervix and noting midcycle pain called mittelschmerz or ovulation pain.

The advantages for using these methods are that the cost is free, the Catholic Church sanctions the methods, and there are no hormones introduced into the body. Often these methods are used to determine the most fertile time of the month when couples are attempting pregnancy. Women become more aware of their bodies as well. The disadvantages are that these methods are very complex and require highly motivated couples willing to abstain from intercourse during fertile times. Conditions that cause the menstrual cycle to be irregular or alter cervical mucus such as breastfeeding or recent childbirth may make these methods more difficult to use.

It is recommended that couples seek professional education and monitoring when learning to use these methods as they often require several cycles of observation to become familiar with the fertility signs and symptoms.

SEE ALSO: Birth control, Menstruation


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