The menstrual cycle is the natural and regular change in a woman’s reproductive system that indicates the release of ova from the ovaries and their movement through the fallopian tube into the uterus for either implantation after fertilization or preparation for a new cycle. The menstrual cycle occurs in stages, which can determine whether a woman can get pregnant or not. The first stage is ovulation, which is when the ovum is released from the ovary. If a woman has sexual intercourse during this time, the sperm meets the ovum in the fallopian tube. In the next stage, the ovum moves into the uterus. A new uterine wall forms in the uterus in preparation for an embryo in case fertilization takes place. The third stage of the menstrual cycle is the shedding of the uterine wall, which flows out through the vagina in the blood (usually called period bleeding). This stage normally happens when fertilization does not occur. Ovulation typically occurs again fourteen days later in preparation for the next cycle, and then the process repeats itself. A normal menstrual cycle occurs every twenty-eight days, but the timing may vary from woman to woman. Although the timing of menstrual cycles differs for each woman, the stages of each cycle remain the same.