Throughout the menstrual cycle a woman's body, one way or another, ready for the birth of a new life. Conception occurs more often in the middle of the cycle, when ovulation occurs. Approximately 11-14 day cycle - the most favorable time. It is in these days much chance of becoming pregnant increases. If you have a cycle longer than 28 days, subtract from the expected date of menstruation 14 days, it will be the time of ovulation the egg. This period can be considered "dangerous".
Chance of becoming pregnant is less than 10 days and after 15 cycles, but everything is very individual. Sometimes ovulation occurs later, and thus the risk of conception increases. It is also necessary to pay attention to the possibility of "failure" in the body. For example, if you have a cold, the egg can mature a little later, for this reason, the day of ovulation slightly postponed.
Do not forget that sperm can live in a woman's body to a few weeks wandering around the vagina, the uterus and tubes. Especially strong instances can wait ripening egg and fertilize it, even if the last sexual relationship did you have after menstruation.
On the basis of all the above, it is possible to accurately understand what "safe" days does not happen. Of course, the chances of getting pregnant at the beginning and at the end of the menstrual cycle is much less, but still do not need to hope and to use the calendar method of protection, especially if you are not ready for childbirth. Calendar method is created rather to calculate ovulation and pregnancy planning, rather than to protect against it. If you just want to move the day, when you see two red stripes on the pregnancy test, but in principle ready to become a mother that you can safely use this method of calculating the "safe" days. But be prepared for anything and do not be surprised if you suddenly feel a slight discomfort and nausea.