The most frequent alterations in the woman's menstrual cycle are:

• Amenorrhea (absence of the period): when there is no blood flow or there is absence of period for several months. Amenorrhea can be primary or secondary: Primary amenorrhea It refers to the lack of periods in a woman who has reached 16 years and has presented normal puberty changes. Secondary amenorrhea It is what happens in a woman who has had rules before and for some reason stops menstruating. Possible causes revolve around ovulation abnormalities, possible birth defects, eating disorders and excessive exercise are some of the most frequent causes.

• Dysmenorrhea (painful bleeding, menstrual cramps): is the menstrual pain. It is divided into primary dysmenorrhea, if it occurs from the beginning of the rules, or secondary, which after a period of non-painful rules begin to be. One of the most frequent causes of severe dysmenorrhea is endometriosis. Essential dysmenorrhea is that which is not accompanied by organic pathology and usually disappears after childbirth.

• Oligomenorrhea (lengthening of the menstrual cycle): the period is normal in duration and intensity, but the intervals are more than 45 days. Oligomenorrhea may be due to a hormonal disorder or simply due to the natural cycle itself. It is more frequent in adolescent girls or in women who approach menopause, but it also occurs in women suffering from certain hormonal diseases or imbalances. This fact is associated with the changes through which the body goes through a stage of hormone-controlled transition. A teenager may need several years for her menstrual cycles to regulate, and women who approach menopause experience a drop in their estrogen levels, resulting in increasingly irregular periods until they finally disappear.

• Polymenorrhea (reduction of the menstrual cycle): the duration of the cycles is less than 21 days, so that the period comes too soon. The cycle can be shortened regularly or irregularly.

• Hypermenorrhea: refers to excessive menstruation within a cycle of a normal duration. If the cycles are also frequent and close, we would be talking about polyhypermenorrhea, synonymous with the previous two terms. Whether it is one or the other pathology, the result is often tiredness or fatigue. This is due in many occasions to the loss of iron, or anemia, implied by the loss of blood.

• Hypomenorrhea: This disorder is common at the onset of menopause, sometimes also in cases of overweight. Bleeding time usually covers only one or two days, or even only a few hours. Many times only one spot appears.

• Metrorrhagia (irregular bleeding): next to normal bleeding, irregular intermenstrual bleeding occurs, which can last several days. It is a hemorrhage or vaginal bleeding produced in the uterus, which occurs outside the female menstrual period. This gynecological imbalance develops due to hormonal dysfunction. This irregular bleeding is a very common problem among adolescents who begin to have the menstrual period, and women who begin the menopause stage.