褚侍中曰∶女人天癸既至，逾十年无男子合，则不调。未逾十年，思男子合，亦不调。不调则旧血不出，新
血误行。或渍而入骨，或变而为肿，或虽合而难子，合多则沥枯虚人，产乳众则血枯杀人。观其精血，思过半矣。
王子亨曰∶经者，常候也。谓候其一身之阴阳愆伏，知其安危，故每月一至。太过不及，皆为不调。阳太过
则先期而至，阴不及则后时而来。其有乍多乍少，断绝不行，崩漏不止，皆由阴阳盛衰所致。
许叔微曰∶妇人病，多是月经乍多乍少，或前或后，时发疼痛。医者一例呼为经病，不辨阴胜阳，阳胜阴，
所以服药少效。盖阴气乘阳，则胞寒气冷，血不营运，经所谓天寒地冻，水凝成冰，故令乍少而在月后。若阳
气乘阴，则血流散溢，经所谓天暑地热，经水沸腾，故令乍多而在月前。当别其阴阳，调其血气，使不相乖，
以平为期也。
陈良甫曰∶妇人月水不调，由风冷乘虚，客于胞中，伤冲任之脉，以损手太阳、手少阴之经也。盖冲任之
脉，起于胞中，人将息顺理，则血气调和，六淫不能为害。若劳伤血气，则风冷乘之，脾胃一伤，饮食渐少，
荣卫日衰，肌肤黄瘦，皆由冲任劳损。故凡遇经行，最宜谨慎，否则与产后证相类。
王子亨曰∶妇人月水不调者，由劳伤气血，致体虚，风冷之气乘之也。冲任之脉，皆起于胞内，为经络之
海。手太阳小肠、手少阴心二经为表里，主上为乳汁，下为月水。若冷热调和，则冲任气盛，太阳少阴所生之
血宣流，根据时而下。若寒温乖适，经脉则虚，如有风冷，虚则乘之，邪抟于血，或寒或温，寒则血结，温则血
消，故月水乍多乍少，为不调也。
Chuzheng (Attendant Chu) stated: Once a woman's Tian Gui (menstrual essence/menses) has arrived, if she does not cohabit with a man for over ten years, her menses will become irregular. If less than ten years have passed, but she desires cohabitation with a man and thus experiences frustration or unfulfilled desire, her menses will also become irregular. When menses are irregular, old blood fails to discharge, and new blood flows erratically. This blood may either seep into the bones or transform into swelling. Even if cohabitation occurs, conception becomes difficult; excessive cohabitation leads to the depletion of essence and blood, causing debility in the person; frequent childbirth and lactation lead to blood exhaustion, which can be fatal. By observing the state of essence and blood, one understands the matter half-way.
Wang Ziheng stated: Menses are a regular physiological indicator. They serve to monitor whether the Yin and Yang of the entire body are deviating or stagnating, thereby indicating health or danger; hence, they occur monthly. Excess or deficiency in volume or timing constitutes irregularity. If Yang is in excess, menses arrive early; if Yin is deficient, menses arrive late. Cases where the flow varies significantly, stops completely, or involves metrorrhagia and metrostaxis are all caused by the fluctuation of Yin and Yang prosperity and decline.
Xu Shuwei stated: Women's diseases often manifest as irregular menstrual volume (either excessive or scanty), irregular timing (early or late), and intermittent pain. Physicians generally label these as "menstrual disorders" without distinguishing between Yin prevailing over Yang or Yang prevailing over Yin; consequently, medication yields little effect. If Yin Qi attacks Yang, the uterus becomes cold, and blood circulation is impaired. As the Classics state, "When heaven is cold and earth frozen, water congeals into ice," leading to scanty flow and delayed menstruation. If Yang Qi attacks Yin, blood flows and spills excessively. As the Classics state, "When heaven is hot and earth warm, menstrual water boils," leading to excessive flow and early menstruation. One must differentiate Yin and Yang imbalances, regulate Qi and Blood, ensure harmony between them, and aim for equilibrium.
Chen Liangfu stated: Irregular menstruation in women results from Wind-Cold pathogens invading due to deficiency, lodging in the uterus, damaging the Chong Mai (Penetrating Vessel) and Ren Mai (Conception Vessel), and subsequently impairing the Hand-Taiyang Small Intestine Meridian and Hand-Shaoyin Heart Meridian. The Chong and Ren Mai originate in the uterus. If the body is nurtured properly and follows natural laws, Qi and Blood remain harmonious, and the Six Evils (Wind, Cold, Summer-heat, Dampness, Dryness, Fire) cannot cause harm. However, if labor and fatigue injure Qi and Blood, Wind-Cold invades. Spleen and Stomach function is damaged, food intake gradually decreases, and Ying (Nutritive) and Wei (Defensive) Qi decline daily. Yellowish complexion and emaciation result from the damage to the Chong and Ren Mai. Therefore, utmost caution is required during menstruation; otherwise, the condition resembles postpartum syndromes.
Wang Ziheng stated: Irregular menstruation in women is caused by labor and fatigue injuring Qi and Blood, leading to physical weakness, allowing Wind-Cold Qi to invade. The Chong and Ren Mai both originate within the uterus and are regarded as the Sea of Meridians. The Hand-Taiyang Small Intestine Meridian and Hand-Shaoyin Heart Meridian are exterior-interior pairs; they govern the transformation of blood into milk above and menses below. If Cold and Heat are balanced, the Qi of Chong and Ren is vigorous, and blood generated by the Taiyang and Shaoyin meridians flows freely according to schedule. If Cold and Heat are mismatched, the meridians become weak. If Wind-Cold is present, it exploits this weakness. Pathogenic factors contend with blood: Cold causes blood coagulation, while Warmth causes blood dissolution. Thus, menses vary in volume, constituting irregularity.