Calendar Based Birth Control
Calendar based, rhythm method, Knaus-Ogino Method, and Standard Days Method of birth control are all various methods of birth control that are based on a woman's previous menstruation history. They are used to either promote conception by timing unprotected intercourse for fertile days, or to avoid conception by only having unprotected intercourse on infertile days. All of these methods come under the umbrella of fertility awareness methods. Do they work? Some work better than others.
The History of the Rhythm Method
The rhythm method of birth control was developed in 1930 by a Roman Catholic doctor from the Netherlands named John Smulders who based his method on knowledge of a woman's menstrual cycle. Independent of and prior to Smulders development, this same method was discovered by Hermann Knaus in Austria and a Japanese doctor named Kyusaku Ogino.
In 1905 a Dutch gynecologist named Theodoor Hendrik van de Velde exhibited that ovulation occurs only once during the menstrual cycle of a woman. It was in the 1920s that Knaus and Ogino independently discovered that ovulation takes place about 14 days before the beginning of the next menstrual cycle. Ogino used his theory to help time conception in infertile women.
Smulder used the Knaus-Ogino information to create a method to avoid pregnancy and published his work with the Dutch Roman Catholic medical association. This became the official rhythm method used from that point forward. A book was published by Dr. Leo Latz, a Catholic physician, in 1932 describing t
he method and John Rock founded the first US Rhythm Clinic in the 1930s to teach Catholic couples the method. For many years the rhythm method of birth control was the only method sanctioned by the Catholic Church as acceptable. However, over the years the Church has adopted several other methods that do not alter the natural function of either the woman or man's body as pills and shots or surgery do.
Fertility awareness and the rhythm method are often considered to be synonymous, however, they are not. Fertility awareness, as mentioned earlier, covers a variety of methods of tracking ovulation through basal body temperature, cervical mucus, or both. These particular methods are known as symptoms-based methods of tracking ovulation. Since the rhythm method's effectiveness has such a poor track record (failure rate of 25%), fertility awareness proponents have chosen to distance themselves from it, considering it to have been obsolete for at least 20 years.
Another mistaken connection is the thought that the rhythm method and natural family planning (NFP) is the same thing. Early on, when the rhythm method of birth control was promoted by the Catholic Church as the only acceptable form of birth control, the method was called NFP. It was the only calendar based method being used at the time, so it followed that the two terms would be synonymous. Today, the term NFP is very broad-based and includes several other types of fertility awareness methods.
In order to use the calendar-based methods, a woman has to know the length of her menstrual cycles. Most menstrual cycles have a pre-ovulatory period at the beginning of the cycle and a post-ovulatory period at the end. In the middle are the fertile days. If the calendar-based methods aren't used perfectly, by not tracking the length of the cycles properly, wrong numbers are used and unprotected sex can take place on a fertile day. That's fine if the couple wants to conceive and definitely not fine if they don't. Imperfect use is quite common because the discipline of keeping flawless track of days is often beyond many people. That is why the failure rate for calendar-based methods of birth control is about 25 percent.
The Standard Days Method, developed in 1999 by Georgetown University's Institute for Reproductive Health, is simpler and more effective than the rhythm method. Using a product called CycleBeads; it has a perfect-use failure rate of five percent. However, it is only truly effective when used by women whose cycles are always between 26 and 32 days in length.