Basic Information about Natural Family Planning Methodology
All NFP methods have the same goal; to help the couple identify the window of fertility that exists between them. The objective is to determine when the woman’s body is ready to ovulate and release an egg. In order to do this, the couple will learn about the naturally reoccurring signs of the female’s fertility. These are called the signs of fertility.
There are two main indicators of fertility that a woman can observe. The first is the cervical fluid discharge and the second is the basal body temperature (her temperature at rest). In addition, there are several secondary indicators that will provide additional information about the window of fertility.
Cervical Fluid – This indicator is the most important indicator of the fertile window. It is
produced by the cervix several days before ovulation. When a woman goes to the bathroom she will see and/or feel this fluid and know that her window of fertility has begun. The fluid becomes more noticeable as ovulation nears and actually peaks when the egg is released. The term peak day is common among NFP methods. It refers to the last day in the cycle when the mucus is most fertile. Peak day is determined in retrospect because the woman has to look back in order to see that the fluid decreased and became less noticeable.
Basal Body Temperature – The basal body temperature makes an upward shift of
approximately half a degree after ovulation. When a woman awakes, she takes her temperature before getting out of bed. Before she ovulates, the temperature will be at her lowest level. After ovulation, the temperature rises and remains elevated. This confirms that ovulation has happened.
Additional Indicators of Fertility – In addition to these main indicators of fertility, there are additional indicators that can also be tracked. Some NFP methods will teach couples how to track the changes that happen at the cervix during the fertile window. Another method will teach a couple how to track the hormonal changes that drive the external observations with the assistance of a hand held fertility monitor. Finally, other methods will teach couples how to use a calendar count of cycle length to determine the possible fertile window with accuracy.
With this knowledge, the couple can accurately divide the menstrual cycle into three parts; the time before ovulation, the fertile window, and the time after ovulation. If the couple wants to achieve a pregnancy, they will engage in sexual intercourse during the fertile window. If a couple wants to postpone a pregnancy, they will engage in sexual intercourse in the time before or after the fertile window.
This information provides a foundational understanding of natural family planning. Now it is time to look at the specifics of the most common NFP methods.
Single Indicator Methods
There are several NFP methods that teach couples how to track the fertile window using only one indicator of fertility. When a method teaches couples how to observe and interpret the cervical fluid indicator only, the method is called an ovulation method. The most common ovulation methods are the Billings Ovulation Method of America® (BOMA), the Creighton Model FertilityCareTM System (CrM), Family of the Americas Foundation Method (FAF) and the Two-Day Method of Fertility Awareness.
Each of the ovulation methods has its own strength. The Billings MethodTM was the first ovulation method developed. It can be learned very quickly and is used by couples around the world. Couples using the Billings MethodTM rely primarily on a sensation or wetness or dryness at the vaginal opening.
The FertilityCareTM method is a standardized model of the Billings MethodTM that is typically taught in a medical setting. It provides couples with a defined grading system for cervical fluids. Because of its standardization, charts tracked in this method can be used to detect underlying menstrual cycle irregularities.
The Family of the Americas method is a simplification of the "mucus” methods. The charting used includes pictures and colors instead of symbols and numbers. The pictorial descriptions are compared to the growing seasons of the year (seeds planted in a time of wetness grow and those planted in a dry time do not.)
Another single indicator method is called the Two Day Method. Women who use the two day method ask themselves two questions every day. Did I observe cervical fluid today? Did I observe cervical mucus yesterday? If she can say no to both questions, she may consider herself infertile.
The final single indicator method is called the Standard Days Method. This method tracks a count of calendar days. When a woman has cycles that are between 26 and 32 days, she has a stable window of fertility that occurs at the same interval in every cycle. In this method, the woman uses a count to tell her when she is fertile and infertile. It is strictly used by women with very regular cycle length.
Multiple Indicator Methods
These methods show a relationship between cervical fluid and the basal body temperature (the temperature of a woman at rest).
Both the Couple to Couple League method and the Sympto-Pro method instruct couples how to observe and interpret the cervical fluid, the basal body temperature, cervical changes and various other secondary signs. Once a couple has learned to observe these indicators, they are given rules to apply that frame the boundaries between the three phases of the cycle. Rules are recommended based on the signs that the couple observes and charts, the reproductive category that the couple is in and the couple’s intention (achieve or avoid). Both methods provides a system of feedback to the couple that helps them refine their understanding of the method.
The Marquette Model is unique in that it teaches couples how to track cervical fluid,
temperature and cervix as well as how to monitor the underlying hormones that drive the
menstrual cycle. Using the Clearblue Easy fertility monitor, the woman can determine the levels of two female hormones that are produced during the fertile window.