The idea behind natural family planning is very simple. A woman is fertile for only about 100 to 120 hours during a month. Let's call this time period the "window of fertility." By avoiding sexual intimacy during the window of fertility, pregnancy can be avoided. This method can also help achieve pregnancy by understanding the fertility cycle better and learning when the probability of conceiving is highest. The question that various natural family planning methods are trying to answer is "How do I determine exactly when the window of fertility starts and ends?" If the window could be determined with 100% accuracy, then natural family planning would be a nearly perfect birth control method. However, the window can only be estimated (estimated though with high probability). To determine the window of fertility, these methods use such things as temperature, mucus, and cervical changes.
What is natural family planning?
Natural family planning is a way to help a couple determine when sexual intercourse can and cannot result in pregnancy. During each menstrual cycle, one of a woman's ovaries releases an egg. This process is called ovulation. The egg moves toward the uterus through the fallopian tubes, where fertilization may take place. An unfertilized egg may live for 12 to 24 hours. The egg will be shed later during the menstrual period if it isn't fertilized. A woman is most likely to become pregnant if sexual intercourse takes place just before or just after ovulation.
During the menstrual cycle, a number of changes occur in a woman's body. By keeping track of these changes, couples can plan when to have intercourse and when to avoid intercourse, depending on whether they are trying to achieve or avoid pregnancy.
How does natural family planning work?
Two methods of natural family planning are currently taught. The first is the ovulation method. In this method, the days just before and just after ovulation are determined by checking the woman's cervical mucus. When a woman is most likely to become pregnant, the cervical mucus is stretchy, clear and slick. Some people say that the cervical mucus during this time looks and feels much like an uncooked egg white.
The second method is called the symptothermal method. With this method, the woman takes her temperature each day with a special thermometer and writes it down on a chart. At the time of ovulation, a woman's temperature will rise slightly. The woman also checks the consistency of her cervical mucus. She may also notice other changes, such as pain in the area of the ovaries, bloating, low backache and breast tenderness.
In both methods, couples use a special chart to keep track of the changes in the woman's body.
How effective are these methods in helping a couple avoid pregnancy?
These methods can help a couple avoid pregnancy if the couple receives training from a specialized instructor and if they carefully follow all of the instructions provided. (Ask your doctor how to find an instructor who is specially trained in teaching natural family planning.) Both methods can be 90% to 98% effective (2 to 10 pregnancies per 100 couples) when they are practiced correctly. However, if a couple doesn't follow the instructions completely, these methods will be much less effective. In practice, these methods may not be as reliable as other forms of birth control.
Can natural family planning help a couple achieve pregnancy?
Yes. As many as 2 out of 3 couples who don't have fertility problems become pregnant if they have sexual intercourse on the days that the cervical mucus is clearest and most stretchable.
What about the rhythm method?
The rhythm method is based on calendar calculations of previous menstrual cycles. This method doesn't allow for normal changes in the menstrual cycle, which are common. The rhythm method isn't as reliable as the ovulation method or the symptothermal method and is generally not recommended. Women who have no variation in the length of their menstrual cycles can use the rhythm method to know when they are ovulating (14 days before the start of their period).
What about women with irregular cycles or who are breast feeding?
It is common for a women to have menstrual cycles that are irregular (either longer or shorter than 28 days). A woman who has irregular menstrual cycles may still be able to tell when she is ovulating by watching for the changes in her body.
Special instructions have been developed for mothers who are breast feeding their babies. Ask your doctor for these instructions if you're breast feeding.
Characteristics of natural family planning
Effectiveness |
2% to 30% failure rate during first year of use; depends on a woman's ability to identify the fertile period of each menstrual cycle and couples' motivation and discipline to practice abstinence when required. |
Age limitations |
No restrictions. |
Parity limitations |
No restrictions. |
Mode of action |
Helps a client prevent pregnancy by avoiding unprotected sexual intercourse during the fertile period of a woman's menstrual cycle. |
Effect on STI risk |
Not protective. |
Drug interaction |
None. |
Duration of use |
Most women can use natural family planning safely throughout their reproductive years (if they are satisfied with the method and have no problems with it). |
Return to fertility |
Immediately upon discontinuation. |
Recent innovations
Recent tested innovations in Natural Family Planning include the Standard Days Method (SDM) and the Two-Day Method, both designed to make natural family planning easier to use for planning or avoiding pregnancy. (Also see the description of Georgetown Institute for Reproductive Health.)
The Standard Days Method is a simple calendar-based method in which users are counseled to abstain from unprotected intercourse on days 8 through 19 of any cycle to avoid a pregnancy. The method is based on recent research that identifies more precisely when a woman is most likely to become pregnant. The concept sought to identify a fixed "window" of fertility, which makes it easier for women to know when during their menstrual cycle they are likely to become pregnant, and when they therefore should not have unprotected intercourse if they want to avoid a pregnancy. This method is simple for service providers to teach and for women to use because there are no calculations or sympto-thermal observations involved. The Georgetown Institute for Reproductive Health describes the advantages and disadvantages of this method, findings from recent studies of acceptability of this method, and program ideas for incorporating this method into a family planning program (GIRH 2004).
The Two-Day Method of natural family planning is based on the identification of the fertile days by monitoring the presence or absence of cervical secretions during the menstrual cycle. This method is grounded in research completed over the last several years on the relationship of fertility signs to actual fertility as well as recent work that more precisely delineates the fertile days of the cycle.
The above articles were adapted from the following web sites:
http://familydoctor.org/126.xml
http://www.rho.org/html/cont-nfp.htm
