The Sympto-Thermal method involves combining several of the natural family planning methods — including, at least, the Basal Body Temperature and (Billings) Ovulation / Mucus methods. These techniques attempt to prevent pregnancy by teaching you to observe your body's fertility signs. Outside this fertile time you can engage in sexual intercourse with complete spontaneity and lower probability of pregnancy. You can also use these methods to increase your chances to achieve pregnancy.
These methods are appropriate for those concerned about side effects or the abortion aspect of contraceptives. Couples also report improved relationships, and increased bodily awareness. After learning, recurring costs are minimal.
The effectiveness of the Sympto-Thermal method (if done perfectly correctly) has been shown to be up to 98%. Since the fertile time can change every cycle, this method is effective even when you are irregular or nursing because you observe your fertility as it happens, and the symptom cross-checks reduce errors as each individual method can be tricky to get accurate.
The Body Temperature method alone is typically 80% effective.
The Ovulation / Mucus method alone is typically 78% effective.
Using the Sympto-Thermal method, you observe the cervical mucus that is produced when you are fertile, near ovulation. Charting your daily temperature once a day will show when you ovulate, confirming that the fertile time is over.
Using the Body Temperature method alone, you attempt to pin-point the time of the month when ovulation occurs. This can be calculated because the body temperature rises after ovulation and stays higher until menstruation. The fertile period can therefore be calculated and you can figure out the days when you can engage in sexual intercourse with a lower risk of pregnancy (as compared to with no birth control).
Using the Ovulation / Mucus method alone, you observe the mucus patterns during the course of your menstrual cycle. By recognizing the changing characteristics of your cervical mucus, you can determine when you're least and most likely to conceive.
Each method should be learned from a physician, family planning center, home study course, book, or certified teachers such as the Couple to Couple League (www.ccli.org). Finding appropriate teachers can be difficult in some areas.
Each technique requires a few minutes a day to observe fertility signs and/or charting; their effectiveness relies heavily on the dedication/ accuracy of the individual. They also require periods of abstinence, or other methods of birth control (e.g condoms), during the fertile periods.
Significant drawback of these methods is lack of protection against STDs.