The menstrual cycle is the scoentific term for the psychological changes that can occur in women for the purposes of fertilization. this article focuses on the human menstrual cycle, a "monthly" cycle that takes approxiamately 28 days to complete although this does vary from person to person. In the menstrual cycle, changes occur in the female reproductive system as well as other systems (which lead to mood changes, for example).
the menstrual cycle, under the control of hormones, is necessary for reproduction. Menstrual cycles are counted from the first day of menstrual bleeding. Hormonal contraception interferes with the normal hormonal changes with the aim of preventing reproduction.
The first stage starts the lining of the uterus breaking out and coming out of the vagina. This is known as a period and usually lasts 5 days. from day 6 to day 13 the lining of the uterus builds up again and the egg in the ovary begins to grow ready to be released. Halfway through the cycle, on day 14, one egg cell slowly moves down the fallopian tubes. If the egg is un-fertilised by day 28 the lining of the uterus breaks down and the egg is ejected from the vagina with the lining.