Software-based Systems
A software program developed in Germany from 1995 to 2001, Perimon is a stricter variant of the rhythm method. It requires a greater period where unprotected sex is not allowed when used to avoid pregnancy, designating a maximum of 10.5 days each cycle as infertile. If 7 of those infertile days occur when a woman's is menstruating, this means there are only 3.5 days of non-menstrual infertile days per cycle.
No clinical studies have been done to determine effectiveness, but the program's developers claim a perfect-use failure rate of 4% per year. The Perimon software requires a paid subscription.
Several Web-based implementations of the cycle method are known. Examples can be found at Menstruation at the Open Directory Project.
Read more about this topic: Calendar-based Contraceptive Methods
Famous quotes containing the word systems:
“What avails it that you are a Christian, if you are not purer than the heathen, if you deny yourself no more, if you are not more religious? I know of many systems of religion esteemed heathenish whose precepts fill the reader with shame, and provoke him to new endeavors, though it be to the performance of rites merely.”
—Henry David Thoreau (1817–1862)