代则气衰，或泄脓血，伤寒心悸，女胎三月。
代亦歇止之脉，但促、结之止，内有所碍，虽止而不全断，中有还意；代则大
止不还，下复至，如更代者。非元气衰微之甚，不至此也。泄脓血者，则营血耗竭，
隧道空虚，故见此欲脱不续之状。（《素问》脉要精微论云∶数动一代者，病在阳之脉也。泄及便
脓血。）伤寒心悸，有中气虚者、有停饮者、有汗下后者。中气虚则阳陷，阳受气于胸中。阳
气陷，则不能上充于胸中，故悸。（宜黄 建中汤之类。）停饮者，饮水多而停于心下也。水
停心下，水气上凌，心不自安，故悸。（宜小青龙汤之类。）汗后则里虚矣，况汗乃心液，
心液耗则心虚，心虚故悸。（宜炙甘草汤、黄 建中汤之类。）诸悸者，未必皆脉代。今脉代者，
正指汗后之悸，以汗为心液，脉为心之合耳。女胎十月而产，腑脏各输真气，资次
培养。一月之时，足厥阴脉养之。足厥阴者，肝也。二月足少阳脉养之。足少阳者，
胆也。三月，手厥阴脉养之。手厥阴者，心胞络也。四月，手少阳脉养之。手少阳
者，三焦也。五月，足太阴脉养之。足太阴者，脾也。六月，足阳明脉养之。足阳
明者，胃也。七月，手太阴脉养之。手太阴者，肺也。八月，手阳明脉养之。手阳
明者，大肠也。九月，足少阴脉养之。足少阴者，肾也。十月，足太阳脉养之。足
太阳者，膀胱也。是以诸经脉各养三十日也。若至期当养之经，虚实不调，则胎孕
为之不安，甚则下血而堕矣。十二经中，独心与小肠不养胎者何欤？夫心为牡脏，
小肠为之腑，主生血而合脉。《素问》平人气象论曰∶藏真通于心，心藏血脉之气也。
有孕则经血不通，许学士所谓妊娠闭经隧以养胎者是也。平人气象论又曰∶妇人手
少阴脉动甚者，妊子也。历观经论、是知胎以血为体，而始终十月，皆赖乎心，自不当
在轮养中又分次第矣。三月之时，心包络养胎。《灵枢》经脉篇云∶心包主脉，若分气
及胎，脉必虚代。在五脏生成篇又云∶心合脉。盖心与心包，虽分二经，原属一脏故耳。
代脉（脉搏有规律的间歇）表示元气衰弱，或者出现泄泻、脓血便的症状，或者是伤寒病引起的心悸，或者是怀孕三个月时的正常脉象。
代脉也是一种歇止脉，但促脉（数而时一止，止无定数）、结脉（缓而时一止，止无定数）的间歇，是因为体内有邪气阻滞，虽然停止但不完全断绝，中间还有回返之意；而代脉则是长时间停止且不返回，下一次跳动重新开始，就像更替代替一样。如果不是元气极度衰微，不会达到这种程度。出现泄泻脓血的情况，是因为营血耗竭，经络隧道空虚，所以呈现出这种想要脱失而不接续的状态。（《素问·脉要精微论》说：脉数动而时有间歇的，是阳分受病的脉象。伴有泄泻及大便脓血。）伤寒引起的心悸，有中气虚弱的、有痰饮停聚的、有发汗或攻下治疗之后的。中气虚弱则阳气下陷，阳气在胸中受纳。阳气下陷，就不能向上充养胸中，所以发生心悸。（适宜用黄芪建中汤之类的方剂。）痰饮停聚的，是因为饮水过多而停滞在心下部位。水饮停滞在心下，水气上凌犯心脏，心脏不能安宁，所以发生心悸。（适宜用小青龙汤之类的方剂。）发汗之后则里气虚弱了，况且汗是心之液，心液耗损则心气虚，心气虚故发生心悸。（适宜用炙甘草汤、黄芪建中汤之类的方剂。）各种心悸症状，未必都是代脉。现在提到代脉，正是指发汗后的心悸，因为汗为心液，脉为心之所合的缘故。
女性怀孕十月分娩，脏腑依次输送真气，按次序培养胎儿。第一个月，足厥阴肝经滋养胎儿。足厥阴经，对应肝脏。第二个月，足少阳胆经滋养胎儿。足少阳经，对应胆腑。第三个月，手厥阴心包经滋养胎儿。手厥阴经，对应心包络。第四个月，手少阳三焦经滋养胎儿。手少阳经，对应三焦腑。第五个月，足太阴脾经滋养胎儿。足太阴经，对应脾脏。第六个月，足阳明胃经滋养胎儿。足阳明经，对应胃腑。第七个月，手太阴肺经滋养胎儿。手太阴经，对应肺脏。第八个月，手阳明大肠经滋养胎儿。手阳明经，对应大肠腑。第九个月，足少阴肾经滋养胎儿。足少阴经，对应肾脏。第十个月，足太阳膀胱经滋养胎儿。足太阳经，对应膀胱腑。因此各条经脉各自滋养三十天。如果到了该滋养的时期，相应的经脉虚实不调，那么胎孕就会不安定，严重时会导致下血流产。十二经脉中，唯独心和小肠不滋养胎孕，为什么呢？心为阳脏（牡脏），小肠为其腑，主生血并与脉相合。《素问·平人气象论》说：脏的真气通达于心，心藏有血脉之气。有了妊娠后，月经血液不通畅，正如许学士所说的“妊娠期间闭塞经络隧道以滋养胎元”那样。《平人气象论》又说：妇女的手少阴脉（神门穴处动脉）搏动明显的，是怀孕了。纵观经典论述，可知胎以血为形体，而整个十月孕期，都依赖于心，自然不应当在轮流滋养中再分先后次第了。第三个月的时候，心包络滋养胎元。《灵枢·经脉篇》说：心包主脉，如果分别供给气和胎，脉气必然虚弱而出现代脉。在《五脏生成篇》中又说：心合于脉。大概心和心包，虽然分为两条经脉，原本属于同一个脏的缘故。
Dai pulse (a regular intermittent pulse) indicates a decline in Yuan Qi (Original Vital Energy), or symptoms of diarrhea with pus and blood, palpitations due to Shanghan (Cold Damage disease), or it is the normal pulse during the third month of pregnancy.
Dai pulse is also an intermitting pulse, but the pauses in Cu pulse (rapid pulse with irregular pauses) and Jie pulse (slow pulse with irregular pauses) are caused by internal obstructions; although they pause, they do not completely cease, retaining a sense of return within the pause. In contrast, Dai pulse involves a long cessation without returning, followed by a restart of the beat, resembling a succession or replacement. Unless the Yuan Qi is extremely depleted, this condition would not occur. Regarding diarrhea with pus and blood, this results from the exhaustion of Ying Blood (Nutritive Blood) and emptiness of the meridians and collaterals, thus presenting as a state of impending collapse and discontinuity. (*Suwen: Pulse Essentials* states: "A rapid, moving pulse with occasional pauses indicates disease in the Yang aspect. It accompanies diarrhea and passage of pus and blood in stool.") Palpitations in Shanghan can stem from deficiency of Zhong Qi (Middle Jiao Qi), retention of Yin (fluids/phlegm), or post-sweating/purging conditions. Deficiency of Zhong Qi leads to sinking of Yang Qi; Yang Qi receives its qi in the chest. When Yang Qi sinks, it cannot ascend to nourish the chest, resulting in palpitations. (Suitable formulas include Huangqi Jianzhong Tang [Astragalus Decoction for Replenishing the Middle]). Retention of Yin occurs when excessive water intake stagnates below the heart. Water stagnation below the heart causes Water Qi to harass the Heart, leading to cardiac insecurity and palpitations. (Suitable formulas include Xiao Qinglong Tang [Minor Blue Dragon Decoction]). After sweating, the interior becomes deficient; moreover, sweat is the fluid of the Heart. Consumption of Heart fluids leads to Heart deficiency, causing palpitations. (Suitable formulas include Zhigancao Tang [Licorice Decoction] and Huangqi Jianzhong Tang). Not all cases of palpitations present with a Dai pulse. The current reference to Dai pulse specifically points to palpitations after sweating, because sweat is the fluid of the Heart, and the pulse is the union of the Heart.
Women give birth after ten months of pregnancy. The Zang-Fu organs successively transmit Yuan Qi to nurture the fetus in sequence. During the first month, the Foot-Jueyin Liver Meridian nourishes the fetus. Foot-Jueyin corresponds to the Liver. During the second month, the Foot-Shaoyang Gallbladder Meridian nourishes the fetus. Foot-Shaoyang corresponds to the Gallbladder. During the third month, the Hand-Jueyin Pericardium Meridian nourishes the fetus. Hand-Jueyin corresponds to the Pericardium. During the fourth month, the Hand-Shaoyang Sanjiao Meridian nourishes the fetus. Hand-Shaoyang corresponds to the Sanjiao. During the fifth month, the Foot-Taiyin Spleen Meridian nourishes the fetus. Foot-Taiyin corresponds to the Spleen. During the sixth month, the Foot-Yangming Stomach Meridian nourishes the fetus. Foot-Yangming corresponds to the Stomach. During the seventh month, the Hand-Taiyin Lung Meridian nourishes the fetus. Hand-Taiyin corresponds to the Lung. During the eighth month, the Hand-Yangming Large Intestine Meridian nourishes the fetus. Hand-Yangming corresponds to the Large Intestine. During the ninth month, the Foot-Shaoyin Kidney Meridian nourishes the fetus. Foot-Shaoyin corresponds to the Kidney. During the tenth month, the Foot-Taiyang Bladder Meridian nourishes the fetus. Foot-Taiyang corresponds to the Bladder. Thus, each meridian nourishes for thirty days. If the corresponding meridian fails to balance deficiency and excess at the appointed time, the fetus becomes unstable, potentially leading to bleeding and miscarriage. Among the twelve meridians, why do only the Heart and Small Intestine not nourish the fetus? The Heart is a Yang organ (Mu Zang), and the Small Intestine is its Fu organ; it governs the generation of blood and unites with the vessels. *Suwen: Normal People's Phenomenon and Image Discussion* states: "The true Qi of the Zang organs communicates with the Heart; the Heart stores the Qi of blood and vessels." Upon pregnancy, menstrual blood ceases to flow, as Scholar Xu described: "During pregnancy, the meridians and collaterals are closed to nourish the fetus." *Pingren Qixiang Lun* further states: "When the Hand-Shaoyin pulse (Shenmen point) moves vigorously in women, it indicates pregnancy." Reviewing classic texts, it is known that the fetus takes blood as its substance, and throughout the ten months, it relies on the Heart. Therefore, it should not be subject to sequential rotation among the other meridians. During the third month, the Pericardium nourishes the fetus. *Lingshu: Meridians Chapter* states: "The Pericardium governs the vessels." If Qi and the fetus were separated, the pulse would necessarily become weak and exhibit Dai characteristics. In *Wuzang Shengcheng Pian*, it is stated: "The Heart unites with the vessels." This is because although the Heart and Pericardium are divided into two meridians, they originally belong to one Zang organ.