Meridians refer to the routes along which qi and blood flow. The meridians that are closely related to the physiological activities of woman are the thoroughfare, conception, governor and belt vessels in the eight extraordinary vessels. The functions of the extraordinary vessels in the human body are to store the qi and blood transported by the twelve meridians and to send out qi and blood for the nourishment of the twelve meridians and viscera. Among the thoroughfare, conception, governor and belt vessels, the thoroughfare and conception vessels are most important in the physiological functions of the reproductive system of women.
The thoroughfare vessel originates from the uterus and moves together with the kidney meridian to the lower abdomen and upward along the navel. It is the region where qi and blood converge, that is why it is called "sea of the twelve meridians", "sea of blood" and "sea of five zang and six fu organs". When woman is well developed, the thoroughfare vessel will be abundant in content and qi and blood from the viscera will flow into the uterus to produce menstruation. The thoroughfare vessel moves upward to connect with the stomach meridian at Qichong(ST 30). So it also governs the production of milk. It is obvious that the thoroughfare vessel is closely related to menstruation, pregnancy and lactation in woman.
The conception vessel starts from the uterus, moving out from perineum and upward along the middle line of abdomen to connect with all yin meridians. The conception vessel governs essence, blood and body fluid. It is the base of pregnancy. That is why it governs pregnancy. The smooth circulation of qi and blood in the conception vessel, in combination with the thoroughfare vessel, is responsible for menstruation and pregnancy.
The governor vessel also starts from the uterus,moving out from the perineum and posteriorly upward along the middle line of the spine to the vertex. It is connected with the spinal cord, brain and all yang meridians.So it is called "the sea of yang meridians". Its branch moves anteriorly and posteriorly from the genitals. The anterior branch is connected with the conception vessel from Cbangqiang (GV 1) point and the posterior branch is connected with the kidney meridian at the end of sacrum and continues to move upward in the spine.
The thoroughfare, conception and governor vessels all start from the uterus, the thoroughfare vessel is the sea of blood and the conception vessel governs uterus and fetus. The governor vessel controls all yang meridians and the conception vessel controls all yin meridians. The balance of yin and yang as well as smooth circulation of qi and blood together maintain normal conditions of menstruation, pregnancy, delivery and lactation.
The belt vessel starts from the hypochondria and moves around the waist like a belt. Its function is to control the meridians moving upward and downward so as to strengthen the connections of meridians. It is significantly related to the thoroughfare, conception and governor vessels which all start from the uterus, together constituting a system in direct relation with the physiological functions of woman. Such a system, in cooperation with the activities of the viscera, not only influences menstruation and pregnancy, but also plays an important role in leuknrrhea and lactation.