The *Zhubing Yuanhou Lun* (Treatise on the Pathogenesis and Manifestations of All Diseases) states: "When the Yin pulse beats vigorously and differs from the Yang pulse, it is called pregnancy. This indicates that Qi and Blood are harmonized, Yang energy is disseminated, and Yin essence is transformed." When palpating the pulse of the Hand-Shaoyin Heart Meridian, if the pulsation is markedly vigorous, it indicates conception. If the Chi (Cun-Kuan-Chi) pulse remains unceasing upon deep pressure, it indicates pregnancy.

The *Chan Jing* (Classic of Childbirth) states: "In women, when the pulses at the three positions (Cun, Guan, Chi) are equal in depth and force during both superficial and deep palpation, this is termed pregnancy." (Current commentary: The *Nan Jing* [Classic of Difficult Issues], Chapter 81, states: 'Three cun distal to the radial styloid process constitute the three positions; thus, each of the Cun, Guan, and Chi positions spans one cun.' Physicians must first understand the principle of the Three Positions and Nine Palpations.)

The *Duan Ju Fang* (Short Formulas) states: "In women who are weak and emaciated, deficient in Qi and Blood, with weak Kidney Qi; or those who have excessively exposed themselves to wind and cold, resulting in phlegm-fluid retention in the epigastrium, when they desire conception, they may easily experience obstruction and illness. What does 'desiring conception' mean? The menstruation still arrives regularly, complexion and skin appear normal, yet the person feels heavy and mentally confused. There is a lack of appetite, the location of the ailment is unknown, and the pulse appears smooth and peaceful when regulated. This indicates a state of desiring conception. After two months from such a state, menstruation ceases, indicating that the fetus has formed." (The *Yufang Mijue* [Secrets of the Jade Chamber] states: "If upon initial ejaculation, the woman's vagina contracts powerfully as if sucking, this is a sign of conception.")

The *Tai Su Jing* (Grand Simplicity Classic) records: "The Xuan Yuan Emperor (Laozi) said: Humans are born through change by receiving the Qi of Heaven and Earth. In the first month, the embryo forms (gao); in the second month, vessels develop; in the third month, the uterus is established; in the fourth month, the fetus takes shape; in the fifth month, sinews grow; in the sixth month, bones form; in the seventh month, the form is complete; in the eighth month, fetal movement occurs; in the ninth month, hair grows (sao refers to body hair); and in the tenth month, birth occurs."

The *Zhou Shu* (Book of Zhou) states: "Humans are generated by the number ten. Heaven has Five Elements, Earth has Five Elements, combining to make ten. The Five Elements of Heaven correspond to the Five Constants, and the Five Elements of Earth correspond to the Five Zang Organs. Thus, the *I Ching* [Book of Changes] says: 'Heaven manifests images, Earth manifests forms.'"

The *Kongzi Jiayu* (Family Sayings of Confucius) states: "One is Heaven, Two is Earth, Three is Humanity. Three times three makes nine; nine times nine makes eighty-one. One governs the day. Since there are roughly thirty days in a lunar month, ten months result in birth."

The *Yufang Mijue* (Secrets of the Jade Chamber) states: "Abundant Yang essence produces a male; abundant Yin essence produces a female. Yang essence constitutes bone, and Yin essence constitutes flesh."