妊娠胎气本乎血气。胎不长者，亦惟血气之不足耳。故于受胎之后而漏血不止者有之，
血不归胎也；妇人中年血气衰败者有之，泉源日涸也；妇人多脾胃病者有之，仓廪薄则化源
亏而冲任穷也；妇人多郁怒者有之，肝气逆则血有不调而胎失所养也。或以血气寒而不长者
，阳气衰则生气少也。或以血热而不长者，火邪盛则真阴损也。凡诸病此者，则宜补宜固，
宜温宜清，但因其病而随机应之，则或以及期，或以过月，胎气渐充，自无不长。惟是年迈
血衰而然者，数在天矣，有非可以人力为也。
妇人有鬼胎之说，岂虚无之鬼气，果能袭人胞宫而遂得成形者乎？此不过由本妇之气质
，盖或以邪思蓄注，血随气结而不散，或以冲任滞逆，脉道壅瘀而不行，是皆内因之病，而
必非外来之邪，盖即血 气瘕之类耳，当即以 瘕之法治之。详见本条。此外如狐
魅异类之遇者，则实有所受而又非鬼胎之谓，亦当于 瘕类求法下之。又凡鬼胎之病，
必以血气不足而兼凝滞者多有之，但见经候不调而预为调补，则必无是病。若其既病，则亦
当以调补元气为主，而继以去积之药乃可也。然用补之外，而欲于补中兼行者，无如决津煎
。欲去其滞而不至猛峻者，无如通瘀煎。既加调补而欲直攻其病者，则夺命丹、回生丹皆可
酌用，或以当归、红花煎浓汤，送赤金豆亦妙。
妊娠期间，胎气的形成根本在于血与气。胎儿发育不良（胎不长），也只是因为血气不足罢了。所以在受孕之后出现阴道出血不止的情况，是因为血液不能归附于胞胎以滋养胎儿；中年妇女出现血气衰败的情况，是因为生命的源泉日渐枯竭；妇女中多有脾胃疾病的情况，是因为脾胃虚弱导致化生之源亏虚，进而使冲脉和任脉气血穷竭；妇女中多有情绪抑郁愤怒的情况，是因为肝气上逆导致血液运行不调，从而使胎儿失去滋养。有的因为血气寒凉而导致胎儿不长，这是因为阳气衰弱，生机减少；有的因为血热而导致胎儿不长，这是因为火邪炽盛损伤了真阴。凡是患有这些疾病的，应当根据病情进行补益或固涩、温阳或清热，只要顺应病机灵活应对，那么胎儿要么能按期出生，要么延期出生，随着胎气逐渐充盈，自然没有不长大的道理。只有那些因为年迈血衰而导致的，那是天数注定，不是人力所能改变的。
妇女中有“鬼胎”的说法，难道虚无缥缈的鬼气，真的能侵袭人的胞宫并因此成形吗？这不过是该妇女自身的体质问题，大概是由于邪念积聚注滞，血液随着气机凝结而不消散；或者是冲任二脉阻滞逆乱，脉道壅塞瘀血而不通行。这些都是内因引起的疾病，必定不是外来的邪气，大概就属于血瘕、气瘕之类的病症，应当立即按照治疗瘕积的方法来治疗。详见本条相关论述。此外，如遇到狐魅异类等怪异情况，则是确实有所感受但又不是鬼胎的概念，也应当在治疗血气瘕积的方法中寻找对策。另外，凡是鬼胎这类疾病，大多是因为血气不足兼有凝滞所致，只要见到月经不调就预先进行调理补益，就一定不会得这种病。如果已经患病，也应当以调理补益元气为主，然后继之以消除积滞的药物才可以。然而在使用补法之外，想要在补益的同时兼行攻逐之法，没有比决津煎更好的方剂。想要去除瘀滞但不至于猛烈峻烈的，没有比通瘀煎更好的方剂。既要加强调补又想直接攻治病邪的，则夺命丹、回生丹都可以酌情使用，或者用当归、红花煎煮浓汤，送服赤金豆也很妙。
Pregnancy and fetal development fundamentally rely on Blood and Qi. Fetal growth retardation (Tai Bu Zhang) is solely due to a deficiency of Blood and Qi. Thus, there are cases where bleeding persists after conception, indicating that Blood fails to return to the fetus for nourishment; there are cases in middle-aged women where Blood and Qi decline and deteriorate, representing the daily depletion of the life source; there are cases among women with frequent Spleen and Stomach disorders, where a thinning of the "granary" (Spleen/Stomach function) leads to a deficit in the source of transformation, thereby exhausting the Chong and Ren vessels; there are cases among women prone to depression and anger, where Liver Qi rebellion causes irregular Blood flow, resulting in the fetus losing its nourishment. Some cases involve coldness of Blood and Qi leading to poor growth, caused by Yang Qi deficiency and reduced vital energy; some involve heat in Blood leading to poor growth, caused by flourishing Fire pathogenic factor damaging True Yin. For all such conditions, treatment should involve tonification or consolidation, warming or clearing, applied flexibly according to the specific pathology. In this way, whether delivering on time or overdue, as fetal Qi gradually fills out, growth will naturally occur. Only when it results from advanced age and declining Blood is it a matter of destiny, beyond human intervention.
The concept of "Ghost Fetus" (Gui Tai) in women: could formless ghostly Qi truly invade the uterus and take shape? This is merely a reflection of the woman's own constitution. It may arise from obsessive thoughts accumulating and stagnating, causing Blood to congeal with Qi without dispersing; or it may stem from stagnation and rebellion in the Chong and Ren vessels, where the pulse channels are obstructed by stasis and fail to circulate. These are all diseases caused by internal factors, definitely not external pathogens, and essentially belong to the category of Blood and Qi masses (Xia). They should be treated immediately using methods for resolving Xia masses. See the relevant section for details. Furthermore, encounters with fox spirits or other strange entities involve actual influences but do not constitute "Ghost Fetus"; one should also seek remedies within the category of treating Blood and Qi masses. Generally, Ghost Fetus disease often involves both Blood and Qi deficiency and stagnation. If menstrual irregularities are identified and addressed with preventive regulation and tonification, this disease can be avoided. If the disease has already occurred, the primary approach must be to regulate and tonify Yuan Qi, followed by the use of drugs to eliminate accumulations. However, among formulas that combine tonification with purgation, Jue Jin Decoction (Juejin Jian) is unparalleled. To remove stagnation without being overly harsh, Tong Yu Decoction (Tongyu Jian) is unmatched. For cases requiring strong tonification while directly attacking the pathology, Mingling Dan (Mingling Pill) or Huisheng Dan (Huisheng Pill) may be used酌情 (at discretion), or thick decoctions of Dang Gui (Angelicae Sinensis Radix) and Hong Hua (Carthami Flos) can be used to administer Chijin Dou (Chijin Bean), which is also excellent.