Both the second and the third phases last seven days. Critical to the third phase from a Western point-of-view is the moment of ovulation. Finally, TCM describes a pre-menstrual phase that also lasts seven days. During the pre-menstrual phase, the yang is stimulated and liver chi is mobilized. The uterus is an interesting organ from a TCM perspective because it is both yin and yang (p. 8). Moreover, the uterus is systematically linked to several other organs: notably the Kidneys and Heart. Proper relationships between Uterus and Kidneys and Uterus and Heart must be maintained. The connection between Heart and Uterus ensures restoration of Blood and proper flow. Liver chi must also flow properly during the time of menstruation (p. 10). Furthermore, the uterus is not conceived of in TCM as an isolated organ but as part of a whole gynecological system that includes fallopian tubes and ovaries. Treatment of any problem related to menstruation varies depending on the patient's symptoms.

Female reproductive organs as a whole are also part of a system, not viewed as separate from any of the five internal organs. The Kidneys may be the most important internal organ in terms of the core essence of menstruation: the Essence that gives rise to the Blood. Any imbalance in Kidney chi can lead to delayed or premature menstruation or similar problems during menopause....

Pulse reading and the appearance of the tongue are main methods used for determining which organs are at the root cause of the problems. Patient cravings for hot or cold liquids can also inform a TCM doctor as to how to treat the underlying problems. Liver and kidney chi problems are especially evident in the tongue diagnosis (p. 13). In addition to the Kidneys, Liver and Spleen also play major roles in the menstrual cycle but all five internal organs interact to create healthy functioning.
Menstruation is also framed in terms of the three Vessels: Governing, Penetrating, and Directing. The Vessels are like energy circuits in the body. The Vessels link organ to organ, system to system. As the term denotes, Vessels allow for the flow of chi along definite channels. Any disruption in the flow of energy in a Vessel will lead to discomfort or illness. Acupuncture is built partly on the principle of the Vessels and how they pave the way for the flow of chi. Moreover, treating with acupuncture can stimulate the organs connected to any Vessel. A blockage of chi can be removed through the stimulation of the needle at particular points. The Vessels are also linked with hormonal fluctuations, offering doctors an opportunity to link together the Western and TCM models…