Natural family planning works best with the sympto-thermal method, which employs all the possible techniques of the natural birth control approach. The sympto-thermal method engages the calendar method, the basal body temperature method, and the cervical mucus method.
This conglomerate approach provides a method of birth control without contraceptives yet is relatively accurate. If you know how to use these natural family planning methods perfectly and in conjunction with each other, the sympto-thermal method is a relatively reliable guide for deciding when to abstain from sex or use a barrier method to avoid unintended pregnancy.
How to use the sympto-thermal method
To use the sympto-thermal method perfectly, you must be able to accurately combine three natural family planning methods: calendar, basal body temperature, and cervical mucus.
The couple uses the calendar method to predict the time of the month when a woman is most fertile. Because sperm can live for several days inside the vagina, this also rules out five days before ovulation.
The couple monitors basal body temperature using a special high-resolution thermometer. A small rise in temperature can indicate ovulation, confirming the calendar method predictions.
The couple monitors the woman’s cervical mucus. If the mucus has thinned, this is another indication of ovulation and, as with the basal body temperature, acts as further confirmation of the calendar method.
Advantages of the sympto-thermal method
If used perfectly, the sympto-thermal method is relatively reliable: of 100 women using it, only 3 will become pregnant. However, under normal use, the number increases to 20.
Natural family planning does provide a birth control method for women who do not want to use contraceptives, and it does so without doctor appointments, major purchases, or side effects.
Disadvantages of the sympto-thermal method
While perfect usage of the sympto-thermal method provides generally reliable prevention of unintended pregnancy, most couples do not use this method perfectly. In fact, under normal usage, 20 percent of women using the periodic abstinence method will become pregnant.
Obviously, these are not great odds, especially since perfect use is rare. That’s because outside factors can play havoc with natural family planning. A few such factors are:
A lack of sleep can cause a woman’s temperature to vary.
The consistency of a woman’s cervical mucus can change if she has a vaginal infection, of which she may not be aware.
Either one of a woman’s ovaries may decide to evict an egg at an irregular interval without any symptomatic warning.
Remember: pregnancy may not be your only risk, and nothing protects you against a sexually transmitted disease except a condom. Unless you are certain that your partner is 100 percent safe, you should make sure that a condom is in place before attempting intercourse.
