Calendar prevention method refers to a natural way to protect against unwanted pregnancy. Its essence lies in the fact that defined "safe" and "dangerous" days. In those days, when the probability of conception is high, it is necessary to abandon the sexual life.
Advantages of the calendar method of birth control that it's free, does not require medical intervention in the body, can be used not only for protection from unwanted pregnancy, but also for the planning of its occurrence.
The main drawback - it is not very high reliability. Any failure in the observations, incorrect calculations, changes in the menstrual cycle can lead to undesirable consequences.
Therefore, this method is the place to be if you have a steady, regular cycle, if you are willing to engage in counting "safe" and "dangerous" days. It is recommended to also maintain appropriate records to avoid confusion.
Today, there are ready-made calendars, which marked the days with a high probability of conception. But you can do the calculations yourself. Usually ovulation occurs about the middle of the cycle. At this time, the chance of pregnancy is very high. But it should be borne in mind that sperm can live in the vagina up to 5 days, so should be considered "dangerous" as 3 to 4 days before ovulation and the same afterwards.
For example, if your cycle is 28 days, then ovulation is 13 - 14 days. Subtract (add) 3 - 4 days, we find that 10 to 17 day cycle should abstain from sex to avoid pregnancy.
When defining "dangerous" days should be noted that in one cycle can occur not ovulate one, but several. Furthermore, it can be moved closer to the beginning or end of a cycle, i.e. it does not necessarily occur in the middle. At the time of ovulation is also influenced by the emotional state of the woman, her hormones. Therefore, to increase the effectiveness of this method can further use another kind of protection of the calendar method.
It is based on the measurement of basal body temperature. Measurements should immediately after waking up, getting out of bed. Measures the temperature using a conventional thermometer, inserting it into the rectum. Hold the thermometer should be about 3 minutes.
The entire menstrual cycle can be divided into two phases: follicular (egg maturation occurs) and luteal. During the first phase of the basal temperature is usually less than 37 °, before ovulation, it sharply decreases. In ovulation and very few days after the temperature rises to 0 4 - 0 6 °. These days are the most "dangerous". Then follows the luteal phase, the temperature at this time is approximately 37 °, sometimes a little higher. Before the onset of menstruation, it falls to 0, 3.
For this method to be effective, must be dynamic to track changes in basal temperature over several cycles. Only after that, you can use it as a means of protection.