Menstruation, moderate in quantity and quality and coming each time at its usual natural time, is the reason for a woman’s health and the cleansing of her body from everything that is harmful due to its quantity and quality; they make a woman temperate and reduce her lusts. According to the average definition of the time of menstruation, a woman should have cleansing every twenty days or up to thirty, and those occurring after a longer or shorter period and occurring on the fifteenth or sixteenth day are unnatural. When the flow of menstruation deviates from its natural state, this causes many diseases; Changes in cleansing times are rare.
The harmful consequences of a change in menstruation in the direction of intensification include weakness of a woman and a change in her appearance; her uterus does not cover the seed well and lusts little, the woman often miscarries and gives birth to weak and frail ones. As for the delay of menstruation and their scarcity, this makes a woman sick from overflow and predisposes her to tumors, pain in the head and all limbs, darkening of the eyes, dullness of senses and fevers. At the same time, the woman’s seminal vessels often become overfilled, and she becomes lustful and intemperate and does not conceive a child during intercourse, since her uterus and semen are spoiled; sometimes this leads to “suffocation of the uterus,” tightness and holding of breath, heart failure and fainting, and often the woman dies. This also results in retention of urine and emission of it drop by drop, since the urinary tract is blocked, and sometimes, especially in girls, hemoptysis and vomiting with blood appear, as well as blood coming out from below. These ailments in such women vary according to the difference in their natures; if a woman has yellow gall, then yellow gall diseases arise in her; if her nature is black bile, then diseases arise in her from black bile; if the nature is mucous, then diseases arise in it from mucus, and if it is bloody, then diseases arise in it from blood. For some women, the cessation of menstruation accelerates and occurs at thirty-five or forty years of age, while for others it is delayed until she reaches fifty years of age. Sometimes the delay of menstruation leads to a change in the qualities of a woman towards masculinity, as we have already said in the paragraph about the delay of menstruation, and sometimes a woman whose menstruation has stopped begins to produce milk, and this serves as a sign that her menstruation has stopped. Often the cessation of menstruation occurs due to compression of the uterus.