Maturation cycle female egg is divided into two phases, on the border of which is ovulation – release of Mature egg to the fallopian tube. Pregnancy in ovulation is most likely, while the viability of the egg keeps for about 3 days.
Studies show that the length of the first phase of the cycle can vary (because of this, different women have periods can occur in different number of days), but the second phase lasts 14 days. Thus, to conceive a child can be from 12 to 14 days of the menstrual cycle (if it lasts 28 days). If the cycle is longer or shorter, the auspicious days are shifted by the difference of the length of the cycle.
From the point of conception to 10 days before menstruation can be considered quite safe. But do not forget that the female body does not always work like clockwork. Earlier maturation of the egg, for example, due to stress or illness. Then the beneficial days for conception moved closer to the onset of anticipated menstruation. Therefore, to judge whether can you get pregnant before menstruation is quite difficult.
The use of the calendar method for the prevention or planning of pregnancy - not the best option, especially for women with irregular menstrual cycle. To accurately determine the date of ovulation in the next cycle, it is necessary to use additional methods, such as measurement of basal body temperature, rapid tests for ovulation, ultrasonography.