《易》曰∶天地氤 ，万物化醇；男女媾精，万物化生。盖天地生生之道，终古为然矣。《颅囟经》曰∶成
胎之后，一月为胞胎，精气凝也，二月为胎形，始成胚也，三月阳神为三魂，四月阴灵为七魄，五月应五行，
分五脏也，六月应六律，定六腑也，七月精开窍通，光明也，八月元神具，降真灵也，九月宫室罗布，以御外侮，
十月受气足，万象成也。此胎元长养，造化自然，非人力也。第妊母脏气护胎，仍若四时之有序∶足厥阴肝、
足少阳胆，属木旺春，养胎在一月二月；手心主包络、手少阳三焦，属火旺夏，养胎在三月四月；足太阴脾、
足阳明胃，属土旺长夏，养胎在五月六月；手太阴肺、手阳明大肠，属金旺秋，养胎在七月八月；足少阴肾，
属水旺冬，养胎在九月。至十月，儿气已足，待时而生。惟手少阴心，君主之官，神明之脏，虽不主月，而无月
不在，其胎元长养，脏气护持，可谓至矣。而人事恣纵败坏，能保其冲任有恒乎？蓄德录曰∶世人无不急于生
子，要知生子之道，精气交媾，溶液成胎。故
少欲之人恒多子，且易育，气固而精凝也；多欲之人常艰子，且易夭，气泄而精薄也。譬之酿酒然，斗米下斗
水，则 酽且耐久，其质全也；斗米倍下水，则淡；三倍四倍则酒非酒，水非水矣，其真元少也。今人夜夜淫
纵，精气妄泄，邪火上升，真阳愈惫，安能成胎？即侥幸生子，又安能必其有成！所以年少生子者，或多羸弱，
欲勤而精薄也；老年生子者，反见强盛，欲少而精全也。且凡嗜于饮者，酒乱其性，精半非真，无非湿热。勤于
欲者，孕后不节，盗泄母阴，耗其胎气，所谓恣纵败坏者，殆以是欤！然父天母地，古人尝言之矣。父主阳施，
犹天雨露；母主阴受，若地资生。胎成之后，阳精之凝，尤仗阴气护养，故胎婴在腹，与母同呼吸、共安危，
而母之饥饱劳逸，喜怒忧惊、食饮寒温、起居慎肆，莫不相为休戚。古人胎教，今实难言。但愿妊娠之母，能
节饮食，适寒暑，戒嗔恚，寡嗜欲则善矣。此尤切于胞胎之急务，幸毋视为泛常而忽之。
《易经》说：天地阴阳之气交融，万物化育醇厚；男女精气交合，万物由此诞生。这大概是天地生生不息的道理，从古至今都是如此。《颅囟经》说：受孕之后，第一个月称为胞胎，是精气凝聚的结果；第二个月形成胎形，开始成为胚胎；第三个月阳神化为三魂；第四个月阴灵化为七魄；第五个月对应五行，分化出五脏；第六个月对应六律，确定六腑；第七个月精气开启窍道，视力光明；第八个月元神具备，降下真灵；第九个月子宫结构完备，以抵御外邪；第十个月受气充足，万象成形。这是胎元生长发育、造化自然的过程，并非人力所能干预。只是怀孕母亲的脏气护持胎儿，仍然像四季运行那样有次序：足厥阴肝经和足少阳胆经，属木而旺于春季，负责养护第一、二个月的胎儿；手厥阴心包经和手少阳三焦经，属火而旺于夏季，负责养护第三、四个月的胎儿；足太阴脾经和足阳明胃经，属土而旺于长夏，负责养护第五、六个月的胎儿；手太阴肺经和手阳明大肠经，属金而旺于秋季，负责养护第七、八个月的胎儿；足少阴肾经，属水而旺于冬季，负责养护第九个月的胎儿。到了第十个月，胎儿气息已足，等待时机出生。只有手少阴心经，作为君主之官、神明之脏，虽然不单独主管某一个月，但没有哪个月不在其中发挥作用。这种胎元的长养和脏气的护持，可以说是达到了极致。然而人事放纵败坏，怎能保证冲任二脉的恒定呢？《蓄德录》说：世人没有不急于求子的，要知道生育的道理，在于精气交媾，溶液成胎。所以欲望少的人往往多子，且容易养育，因为气固精凝；欲望多的人往往难生子，且孩子容易夭折，因为气泄精薄。这就好比酿酒一样，一斗米加一斗水，酒就浓烈且耐久，其本质完整；一斗米加倍加水，酒就变淡；加三倍四倍的水，那就不是酒也不是水了，其真元就少了。现在的人每晚纵欲，精气妄泄，邪火上升，真阳更加疲惫，怎么能成胎呢？即使侥幸生下孩子，又怎么能保证他能健康成长！所以年轻时生子的人，往往身体羸弱，是因为欲望勤而精气薄弱；年老时生子的人，反而显得强盛，是因为欲望少而精气完整。而且凡是嗜好饮酒的人，酒扰乱本性，精子半真半假，无非是湿热。勤于欲望的人，怀孕后不加节制，暗中耗泄母体阴气，消耗胎气，所谓的放纵败坏，大概就是这样吧！然而父天母地，古人曾经说过了。父亲主阳气施予，如同天降雨露；母亲主阴气承受，如同大地滋养生命。胎成之后，阳精的凝聚，尤其依靠阴气来护养，所以胎儿在腹中，与母亲同呼吸、共安危，而母亲的饥饱劳逸、喜怒忧惊、饮食寒温、起居谨慎或放肆，无不相互关联，休戚与共。古人的胎教，现在实在难以详述。只希望怀孕的母亲，能节制饮食，适应寒暑，戒除愤怒，减少嗜欲，这样就很好了。这更是关乎胞胎的紧急事务，希望不要视为平常小事而忽视它。
The *Book of Changes* states: "When the Qi of Heaven and Earth blends, all things are transformed with richness; when male and female essence interact, all things are born." This is likely the way of Heaven and Earth generating life, unchanged from ancient times to the present. The *Cranium and Fontanelle Classic* (*Lunxin Jing*) states: After conception, in the first month it is called a "bao tai" (fetal sac), which is the condensation of essence and Qi; in the second month, the fetal form appears, beginning as an embryo; in the third month, Yang Spirit transforms into the Three Souls; in the fourth month, Yin Spirit transforms into the Seven Po; in the fifth month, it corresponds to the Five Elements, differentiating the Five Zang Organs; in the sixth month, it corresponds to the Six Pitch-pipes, determining the Six Fu Organs; in the seventh month, essence opens the orifices, bringing light/vision; in the eighth month, Yuan Shen (Original Spirit) is complete, descending true spirit; in the ninth month, the palace (uterus) is fully structured to defend against external evils; in the tenth month, received Qi is sufficient, and all phenomena are formed. This growth and nourishment of the fetal origin follows natural creation, not human effort. However, the maternal Zang organ Qi protecting the fetus still follows an order like the four seasons: The Foot Jueyin Liver and Foot Shaoyang Gallbladder belong to Wood and prosper in Spring, nourishing the fetus in the first and second months; the Hand Jueyin Pericardium and Hand Shaoyang Sanjiao belong to Fire and prosper in Summer, nourishing the fetus in the third and fourth months; the Foot Taiyin Spleen and Foot Yangming Stomach belong to Earth and prosper in Late Summer, nourishing the fetus in the fifth and sixth months; the Hand Taiyin Lung and Hand Yangming Large Intestine belong to Metal and prosper in Autumn, nourishing the fetus in the seventh and eighth months; the Foot Shaoyin Kidney belongs to Water and prospers in Winter, nourishing the fetus in the ninth month. By the tenth month, the child's Qi is sufficient, waiting for the time to be born. Only the Hand Shaoyin Heart, the official of the sovereign and the viscera of Shen Ming (Spirit), although not governing a specific month alone, is present in every month. The nourishment of the fetal origin and the protection by Zang organ Qi can be said to be perfect. Yet, if human conduct is indulgent and destructive, how can one ensure the constancy of the Chong and Ren vessels? The *Xude Lu* says: People are eager to have children, but one must know that the way of childbirth lies in the interaction of essence and Qi, forming the fetus through solution. Therefore, those with few desires often have many children and they are easy to raise, because their Qi is solid and Essence is condensed; those with excessive desires often struggle to conceive and their children may die young, because their Qi leaks and Essence is thin. It is like brewing wine: adding one dou of water to one dou of rice makes strong and durable wine, preserving its substance; doubling the water makes it weak; tripling or quadrupling it results in neither wine nor water, losing its true Yuan Qi. Today, people indulge nightly, leaking essence recklessly, causing evil fire to rise and True Yang to become exhausted. How can they conceive? Even if they luckily bear a child, how can they guarantee its healthy development? Thus, those who conceive at a young age often have frail children, due to frequent desire and thin essence; those who conceive at an older age often have robust children, due to less desire and complete essence. Furthermore, those addicted to alcohol have their nature disturbed by wine, resulting in sperm that is half-true and half-damp-heat. Those diligent in desire, lacking restraint after pregnancy, secretly drain the mother's Yin and consume fetal Qi. Such indulgence and destruction likely stem from this. As ancients said, Father is Heaven and Mother is Earth. The father governs Yang giving, like rain and dew from heaven; the mother governs Yin receiving, like earth nurturing life. After conception, the condensation of Yang essence relies heavily on Yin Qi for protection. Thus, while in the womb, the fetus breathes and shares safety/danger with the mother. The mother's hunger/fullness, labor/rest, joy/anger/worry/fright, diet temperature, and cautious or reckless daily habits are all interconnected and share weal and woe. Ancient prenatal education is hard to describe in detail today. I only hope that pregnant mothers can regulate diet, adapt to cold and heat, abstain from anger, and reduce desires. This is the urgent task concerning the fetal sac; do not treat it as trivial and ignore it.