Natural family planning (NFP) is fertility awareness, which is simply knowledge of a couple’s fertility. It is a means of reading the body’s signs of fertility and infertility; applying this knowledge through the Sympto-Thermal Method (STM) is over 99% effective in postponing pregnancy. A married couple’s virtuous application of this knowledge either to try to achieve a pregnancy or to postpone a pregnancy is called responsible parenthood.
Practicing NFP is 100% natural — there are no drugs, chemicals or devices involved, which is one reason many today find it to be a positive and refreshing alternative to contraceptive methods. NFP honors our dignity as persons by respecting the natural rhythms and functions of the body. It is very common to hear couples who use NFP speak of an increased awe and respect for femininity and their mutual fertility, and a greater sense of empowerment through self-knowledge.
The fertility cycle
The female fertility cycle can be divided into three phases.
Phase I begins on the first day of menstrual bleeding, and normally includes a few infertile days after menstruation.
Phase II begins as soon as a woman’s daily observations detect the onset of signs of fertility. This fertile time lasts up to and a few days after the time of ovulation (when an egg is released from the ovary). In a normal, healthy woman, Phase II will typically last up to 12 days.
Phase III is the post-ovulation time and is a time of infertility. Phase III typically accounts for the last one-third of a healthy woman’s cycle.
The three phases of the female cycle are the result of the interplay of four key hormones – estrogen, progesterone, follicle-stimulating hormone and luteinizing hormone. These hormones are also responsible for the fertility signs that a woman can learn to observe.
The Sympto-Thermal Method
The Sympto-Thermal Method (STM) taught by CCL is based on three key signs of fertility: cervical mucus, basal body temperature and changes in the cervix. By observing and recording these signs you and your spouse will be able to identify Phase I, II and III and therefore know if you’re in a time of fertility or infertility.
These signs are easily noticed by any woman who has learned to watch for them. It takes only a minute or two each day to record them in CCL’s mobile app, CycleProGo, or on a paper chart. The chart provides a daily record that can be used to identify the days of fertility and infertility. Once the fertile and infertile days have been identified, couples apply “rules” that they learn in class (and that are explained in CCL’s Student Guide) to frame the boundaries between the phases of the cycle.
(The above description is taken from the Couple to Couple League's Website which teaches the Sympto Thermal Method. This is the method taught at St. Mary. For information about other forms of NFP and where they are taught go to: http://catholicdioceseofwichita.org/nfp )