Summary:
The modern NFP methods which monitor cervical mucus and other symptoms throughout each woman's individual cycle (Billings, Creighton, Sympto-Thermal) should always be recommended over the historical methods. The historical methods often offer simplicity however compromise efficacy and therefore should not be recommended. The old rhythm-calendar method often fails since women only ovulate on day 14 about 10% of the time, and they may ovulate on a different day each month. Any kind of stress can delay ovulation therefore confining ovulation to set day ranges is inaccurate. Models based on population-derived probability data are not as good as individualized symptoms which respond to the individual cycle of each woman. Retrospective data is not as useful for predicting fertility but are rather used for confirming ovulation after the fact. Body temperature may increase 6-8 days after ovulation with a BBT only method, so it may be an unreliable measure of ovulation. Also, you need a corpus luteum for temperature to increase, which is absent in breastfeeding or amenorrhea.
1. Rhythm/Calendar Old model, less effective, based on probability.
2. Basal Body Temperature No prediction of ovulation, not specific.
3. Standard Days }Easy to teach, less effective, based on probability.
4. Two Day Simple to use, less effective, mucus presence not specific to context within cycle.
Reference:
1) Jennings, V. Fertility Awareness-Based Methods of Pregnancy Prevention. In: UpToDate, Zieman M, and Barss VA (Ed). UpToDate, Waltham, MA, 2013.
The modern NFP methods which monitor cervical mucus and other symptoms throughout each woman's individual cycle (Billings, Creighton, Sympto-Thermal) should always be recommended over the historical methods. The historical methods often offer simplicity however compromise efficacy and therefore should not be recommended. The old rhythm-calendar method often fails since women only ovulate on day 14 about 10% of the time, and they may ovulate on a different day each month. Any kind of stress can delay ovulation therefore confining ovulation to set day ranges is inaccurate. Models based on population-derived probability data are not as good as individualized symptoms which respond to the individual cycle of each woman. Retrospective data is not as useful for predicting fertility but are rather used for confirming ovulation after the fact. Body temperature may increase 6-8 days after ovulation with a BBT only method, so it may be an unreliable measure of ovulation. Also, you need a corpus luteum for temperature to increase, which is absent in breastfeeding or amenorrhea.
1. Rhythm/Calendar Old model, less effective, based on probability.
2. Basal Body Temperature No prediction of ovulation, not specific.
3. Standard Days }Easy to teach, less effective, based on probability.
4. Two Day Simple to use, less effective, mucus presence not specific to context within cycle.
Reference:
1) Jennings, V. Fertility Awareness-Based Methods of Pregnancy Prevention. In: UpToDate, Zieman M, and Barss VA (Ed). UpToDate, Waltham, MA, 2013.