According to Traditional Chinese Medicine (TCM) theory, the causes of missed period (amenorrhea) are nothing more than factors like emotional distress, improper diet, blood deficiency, and cold evil and damp turbidity attacks. These factors cause dysfunctions of internal organs and blockages the two extra meridians, the Thoroughfare Vessel and the Conception Vessel, resulting in blood and qi (vital energy) cannot flow through the extra meridians to reach the uterus and form menses.

In order to facilitate clinical management, physicians usually divide the pathological changes of the body as either deficient or excess states.

Pathological development of missed period from a TCM perspective

Deficient states that result in the development of missed period

Deficiency of kidney-qi: kidney-qi is regarded as the power for menstruation in TCM. When kidney-qi deficiency occurs, the kidneys will then fail to produce a substance called tian gui, and the blood will not flow to the Thoroughfare Vessel and Conception Vessel. This usually happens in aging, chronic illness or miscarriage.

Depletion of kidney essence : kidney stores essence; blood and essence are mutually transformed. Essence is an important source for blood formation. When there is inadequate essence, there is inadequate blood accumulated in the uterus, and so no menses are formed. This usually happens with overwork and after multiple pregnancies.

Deficiency of spleen and stomach: this means that the body's digestive and absorption functions are under-functioning, which leads to poor transformation of nutrient essence for the production of blood and qi (vital energy). This usually happens with stress, overwork and an improper diet.

Stagnation of qi and blood: this is usually due to emotional disorders. Emotional health depends on a smooth flow of qi (vital energy) and blood, which are mainly regulated by the liver. In cases of emotional distress especially depression and anxiety, the liver's regulating function is impaired and a condition termed "stagnation of liver-qi" results. When internal qi and blood flows become disturbed, the extra meridians are affected and the menses will not come regularly.

Obstructions in the extra meridians: When the body has accumulated excess pathogens such as coldness and dampness evils, they tend to obstruct the Thoroughfare Vessel and Conception Vessel, and therefore disturb the blood and qi flows. On the other hand, dysfunction in the spleen or kidney leads to phlegm and dampness formation internally. When they accumulate in the extra meridians or uterus, blockages form.

Excessive heat: this is a rare phenomenon, when the body has accumulated excessive heat evils, they dry up the blood fluid and cause missed period.