So what is menstruation? It is nothing more than the shedding of coagulated endometrial blood that accumulates at the bottom of the uterus to receive the fertilized egg during the fertile period. If fertilization does not occur, the blood breaks down and exits as blood through the vagina. We can say that menstruation is the shedding of the endometrium due to the hormonal decrease during the luteal phase.

The usual appearance of menstruation is the presence of bright red blood, darker red, brown, mucus (a sign of estrogenic change), or brown discharge with flow. Menstruation with a low amount of flow is possible, but one should always watch for changes in volume and quantity. All these changes may mean that estrogen or progesterone levels are below or above the expected range. For example, a brown menstruation may indicate that progesterone is low and estrogen is high during that cycle.

Bright red blood may indicate the healthiest menstruation of all, but if accompanied by clots, it can also mean a hormonal increase. Menstruation with lighter and pinkish blood means that the endometrium is thin and there was not enough stimulation for the uterine walls to thicken.

The menstrual cycle varies from woman to woman: for some, early menstruation is common, for others, late menstruation is usual, but for all it definitely has to do with hormones and can be uncomfortable. No cycle is exactly the same as another for some women; irregular menstruation can often be an inconvenience, since it is of no help for those who want to get pregnant—it's torture not knowing exactly when you will ovulate. This irregularity of coming early, late, or sometimes going months without appearing, is due to hormonal imbalance and disharmony.