The calendar method of protection from pregnancy was developed in the 1920s by the Japanese gynecologist Ogino and the Austrian Knaus. The method is based on calculating the estimated date of ovulation and abstinence from sexual intercourse in the most fertile days for conception. The calendar method is one of the most unreliable. From 9 to 40% of women using this method become pregnant. Therefore, a more advanced calendar method of protection was developed - a symptomatic method. In addition to calculating the date of ovulation, it takes into account the physiological state of the woman.
The calendar method of Ogino-Knows
This method is the most natural method of protection. It is based only on observations and calculations. Due to the maximum non-interference in the body's natural processes, the calendar method is the only method of protection approved by the Roman Catholic Church.
The essence of the method is as follows. After sexual intercourse in the vagina, spermatozoa survive only a few hours. And getting to the cervix they are active from 2 days to a week. Ovum in ovulation (exit from the ovary) can only be fertilized within 24 hours. Knowing the beginning of ovulation, you can plan to engage in sex so that even theoretically not allow an unwanted pregnancy. To successfully apply the calendar method of Ogino-Knaus, it is necessary to fill the calendar of menstrual cycles throughout the year. However, this method is suitable only for women with a regular menstrual cycle. The slightest failure in the hormonal system, illness, nervous shock can shift the menstrual cycle and lead to errors in the calculations. And, consequently - to pregnancy.
By the method of Ogino-Knaus, you can calculate "dangerous" days (favorable for conception):
- The beginning of the "dangerous" (fertile) period is calculated by the formula: the duration of the shortest cycle is 18 days;
- The end of the fertile period is calculated by the formula: the duration of the longest cycle is 11 days.
For example, observing the last 12 cycles, you calculated that the shortest cycle was 26 days, and the longest was 32 days. It turns out that from 8 days (26-18) to 21 days (32-11) of the cycle (and the first day of the cycle is considered the first day of menstruation) are the most favorable for conception. If the goal is to be safe from pregnancy, then these days it is necessary to abstain from sexual acts, or to be protected in other ways. And vice versa, from 1 to 8 days, as well as from 21 days to the end of the cycle, this method can not be protected.
For protection this method is not the best. But for the planning of pregnancy this method is very effective.
Symptomatic calendar method
It is known that with a 28-day cycle, ovulation occurs on the 14th day of the menstrual cycle. But this is averaged value. For many women, the cycle is somewhat different, and ovulation occurs a little earlier or a little later. Taking into account the shortcomings of protection from pregnancy in Ogino-Knaus, experts suggested adding the date of ovulation in the calendar with three more parameters. The first is the control of body temperature (temperature method). The second is the control of the state of cervical mucus secreted from the uterus (cervical method). The third is control of the change in the position of the cervix, its softness and openness. The results of all these observations are recorded in a special calendar, according to which the safer days for sex are determined.
The effectiveness of the symptomatic calendar method is incredibly high. It is second only to complete sterilization. With proper use, only 3 women out of 1000 have an unplanned pregnancy (0.3%!). This is comparable to the hormonal method and is much higher than other methods of contraception. However, this method does not protect against genital infections. For successful application of the symptomatic method, it is important to monitor your condition on a daily basis. For observations it takes about 10 minutes a day. The method at first seems difficult and before its application it is recommended to undergo practical training.