The calendar method of contraception is a natural method for preventing pregnancy that’s carried out by keeping track of days when fertility is most likely and refraining from sexual intercourse during those periods. A woman might choose this birth control method for a variety of reasons. Some women are unable to tolerate the hormones found in birth control pills, while others choose the calendar method for personal or religious reasons. Unlike other birth control methods, the calendar method is time intensive, requiring considerable effort on a woman’s part to track times when she’s most fertile.
How Does the Calendar Method of Contraception Work?
The idea behind the calendar method of contraception is to follow the menstrual cycle for eight months to a year, documenting each day of the cycle on a calendar. By keeping careful records, both the shortest and longest cycle can be determined. Once that’s known, the first fertile day can be calculated by subtracting 18 from the length of the shortest cycle. The last fertile day is calculated by subtracting 11 from the longest cycle. To avoid pregnancy, sexual intercourse is avoided from the first to the last fertile day. It’s important that cycles be followed for at least eight months to establish a pattern before relying on this method to prevent pregnancy. It’s more likely to be a reliable method of birth control for women who have regular cycles.
What are the Advantages of This Birth Control Method?
One advantage to using the calendar method of contraception is it doesn’t expose a woman to synthetic hormones such as those found in the birth control pill. This is of particular concern since the birth control pill has been associated with an increased risk of breast cancer in some studies. The use of spermicides along with condoms can increase the risk of urinary tract infections, while intrauterine devices can cause heavy menstrual bleeding and cramping. The calendar method of birth control offers none of these disadvantages. It’s a completely natural, hormone-free way to prevent pregnancy. Another advantage is that it costs nothing to use this method. All that’s needed is a calendar to record the menstrual cycle.
What are the Disadvantages of the Calendar Method of Contraception?
Of course this method of birth control also has its disadvantages. Besides being time intensive and requiring effort to establish periods of fertility, the calendar method has a relatively high failure rate. According to Planned Parenthood, if one-hundred women use this method for a year, nine will become pregnant. Some sources list the failure rate as high as twenty percent. It’s also not a good birth control method for women who have irregular periods or short cycles (less than twenty-seven days). Finally, it limits the number of days that intercourse is safe without risking pregnancy.
The Final Word
The calendar method of contraception may be suitable for a highly motivated couple who’s willing to put in the time and effort needed to track cycles or for those who don’t want to use other forms of birth control. Keep in mind this method has the highest failure rate of any form of birth control.
References:
Planned Parenthood
Blueprints Family Medicine. Martin S. Lipsky, Mitchell S. King. pp. 218-219
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