reproductive cycle

Almost 90% of women have cycles of 25-35 days and only 10-15% of which has a length of 28-day cycle, but some women have irregular cycles and this could be an indication of fertility problems.
The length of the menstrual cycle is calculated from the first day of menstrual period is when the first bleeding starts is called the first day which is then counted until the last day - that is 1 day before menstrual bleeding begins next month.
A woman has two ovaries each ovary store about 200,000 to 400,000 immature eggs / follicles (follicles). Normally, only one or a few eggs to grow each menstrual period and around day 14 before the next menstrual period, when the egg has been cooked, the egg will be released from the ovary and then walked to the fallopian tubes to then be fertilized. Release process is called "ovulation".
At the beginning of the cycle, a gland in the brain releases a hormone called Follicle Stimulating Hormone (FSH) into the bloodstream so that makes egg cells are grown in the ovary. One or a few eggs and then grow faster than other eggs and become dominant until then began to produce a hormone called estrogen is released into the bloodstream. The hormone estrogen helps in cooperation with the hormone FSH dominant egg cells are grown and then gave the signal to the uterus to prepare to receive the egg cell. Hormone estrogen also produce more mucus in the vagina to help the survival of sperm after having sex.
In the meantime, to "welcome" the egg cell that has been released, the lining of the uterus begin to thicken and the walls are softened. If no fertilization occurs, the blood and tissues that make the uterine lining to thicken so that the decay of unused and out through the vagina. This cycle normally occurs every month and quit after the ovaries no longer release an egg, this time called menopause.
If you want to get pregnant, the chance of pregnancy is big enough if sexual relations conducted at around the time of ovulation is usually 2-5 days. To detect the occurrence of ovulation, some women using basal body temperature and mucus. Body temperature usually increases after ovulation and continues to increase until several days afterward. The resulting viscous cervical mucus usually occurs just before ovulation. This fertile mucus helps the sperm cells move toward the egg. Once fertilized, the egg will stick to the lining of the uterus.