Natural family planning methods involve identifying the fertile days of the menstrual cycle using a combination of cycle length and physical manifestations of ovulation (change in cervical secretions, basal body temperature). Once this period is identified, sexual intercourse is avoided or barrier methods are used on those particular days. These fertility awareness-based methods can be 75–96% effective at preventing pregnancy. Efficacy rates tend to be higher after the learning process which takes 3-4 months.
The optimal method is one that is easy to use and reduces the number of days that intercourse must be avoided or practiced with a barrier contraceptive such as a condom.
Standard Days Method
SDM works for women with menstrual cycles from 26 to 32 days long. To use the method, couples abstain from sexual intercourse on days 8 through 19 of the woman’s menstrual cycle. If a woman has more than one cycle per year that is shorter than 26 days, or longer than 32 days, the method effectiveness decreases significantly and a different method of NFP should be used. This method can be aided by the use of CycleBeads or an iCycleBeads application to track cycle days. This method can be up to 95% effective with perfect use, but is more likely to be around 88% effective with average use.
There are two ways to use this method, the Billings method or the TwoDay method.
• The Billings method is the oldest method of observing cervical secretions to determine the fertile period. This method takes time and practice by learning to observe, record, and interpret cervical secretions, paying close attention to the color, elasticity, amount, and viscosity. Unprotected intercourse should be avoided on menses, on pre-ovulatory days following days with intercourse due to the possible confusion with semen, on all days with wet, slippery, transparent, or stretchy secretions consistent with ovulation, and until four days past the last day with wet secretions. Based on these rules, you need to avoid unprotected intercourse for approximately 14 to 17 days of each cycle. This method can be up to 97% effect with perfect use but more likely around 77% with typical use.
• The TwoDay method uses the presence or absence of cervical secretions in determining the fertile period. Unprotected intercourse should be avoided on all days that secretions are noted as well as the first day following a day with secretions. This method can be up to 97% effective with perfect use but is around 86% effective with typical use.
The symptothermal method uses changes in cervical secretions and basal body temperature to identify the fertile period. The presence of wet, slippery, transparent, or stretchy cervical secretions indicates the start of the fertile phase of the cycle and a basal body temperature (BBT) elevation serves as an indicator of the end of the fertile phase. The symptothermal method requires the observation and recording of cervical secretions as well as temperatures with a BBT thermometer each morning before rising.
Unprotected intercourse should be avoided on all days with secretions, on all pre-ovulatory days following days with intercourse because of the possible confusion with semen, and until three days of higher temperatures have followed at least six days of lower temperatures, or the fourth day after the last day with wet secretions, whichever happens later. This method can be up to 98% effective but is more likely to be around 80-85% effective with typical use.
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