巢元方曰∶妊娠受胎在腹，七日一变。今妇人堕胎，在三月五月七月者多，在二月四月六月者少。脏阴而
腑阳，三月属心，五月属脾，七月属肺，皆在五脏之脉，阴常易亏，故多堕耳。如在三月曾堕，后受孕至三月
亦堕，以心脉受伤也，先须调心。五月七月亦然，唯一月堕胎，人皆不知也。一月属肝，怒则多堕，洗下体则
窍开亦堕。一次既堕，肝脉受伤，下次亦堕。今之无子者，大半是一
月堕胎，非尽不受孕也。故凡初交后，最宜将息，勿复交接，以扰子宫。勿令劳怒，勿举重，勿洗浴，又多服养
肝平气药，则胎固矣。
孙《千金》曰∶凡女人受孕，经三月而堕者，虽气血不足，乃中冲脉有伤。中冲脉即阳明胃经供应，胎孕至
此时，必须节饮食，绝欲戒怒，庶免堕胎之患。
潘硕甫曰∶巢氏论诸经脉养胎，各三十日，而十二经中，独心与小肠不养胎，何也？心为牡脏，小肠为腑，
主生血而合脉，经曰脏真通于心，心藏血脉之气也。有孕则经脉不通，许学士所谓闭经以养胎是也。是知胎
以血为本，始终皆在于心，自不当以输养分次第矣。三月之时，心包络养胎。《灵枢》云心包主脉，若分气及
胎，脉必虚代。经云心合脉，盖心与包虽分二经，其实原属一脏故也。若至期，当养之经，虚实不调，则胎不
安，甚则下血而堕矣。
巢元方说：妊娠受孕后，胎儿在腹中每七天发生一次变化。现在妇女堕胎，发生在怀孕第三个月、第五个月和第七个月的较多，发生在第二个月、第四个月和第六个月的较少。脏属阴而腑属阳，第三个月对应心，第五个月对应脾，第七个月对应肺，这些都属于五脏的经脉，阴气容易亏损，所以容易发生堕胎。如果在第三个月曾经堕胎，后来再次受孕到第三个月时又堕胎，这是因为心脉（主管心脏功能的经脉）受到了损伤，必须先调理心脏。第五个月和第七个月的情况也是如此，只是第一个月堕胎，人们都不知晓罢了。第一个月对应肝，发怒容易导致堕胎，清洗下身则下体窍穴张开也会导致堕胎。一旦有一次堕胎经历，肝脉就会受伤，下次怀孕也容易堕胎。现在没有子女的人，大半是因为第一个月有过堕胎经历，并非完全不能受孕。所以凡是初次同房后，最适宜静养休息，不要再行房事，以免扰乱子宫。不要让自己劳累或愤怒，不要举重物，不要洗浴，并且多服用滋养肝脏、平抑气机的药物，那么胎儿就能稳固了。
孙思邈在《千金方》中说：凡是妇女受孕后，在怀孕三个月时堕胎的，虽然气血不足，但主要是因为中冲脉（即足阳明胃经，负责供应胎孕营养的经脉）受到了损伤。到了这个时候，必须节制饮食，断绝性欲并戒除愤怒，这样才能避免堕胎的祸患。
潘硕甫说：巢元方论述各条经脉养育胎儿，每条经脉负责三十天，而在十二正经中，唯独心和手少阳小肠经不直接养育胎儿，这是为什么呢？心为阳脏（牡脏），小肠为腑，主要功能是生成血液并与脉相连，《内经》说“脏真之气通于心”，心藏有血脉之气。有了妊娠后，经脉运行受阻，正如许学士所说，通过闭经来供养胎儿。由此可知，胎儿以血为本，从头到尾都与心有关，自然不应当按顺序分配输养分给各经。在怀孕第三个月时，由心包络（保护心脏的外围组织及经脉）来养育胎儿。《灵枢》说心包主司脉的功能，如果分出一部分气及血来供养胎儿，脉象必然会出现虚代（虚弱且间歇）的现象。经文说“心合于脉”，大概因为心和心包虽然分为两条经脉，但实际上原本属于同一个脏器。如果到了该经脉养育胎儿的时期，该经脉虚实不调，那么胎儿就不安稳，严重时会出现阴道出血而堕胎。
Chao Yuanfang stated: After conception, the fetus in the abdomen changes every seven days. Currently, among women who suffer miscarriage, it occurs more frequently in the third, fifth, and seventh months of pregnancy, and less frequently in the second, fourth, and sixth months. Zang organs are Yin, while Fu organs are Yang. The third month corresponds to the Heart, the fifth month to the Spleen, and the seventh month to the Lung; these all belong to the meridians of the Five Zang organs. Since Yin is prone to deficiency, miscarriage is common. If a miscarriage occurred in the third month previously, and upon conceiving again, another miscarriage happens at the third month, it is because the Heart Meridian (the meridian governing the heart's functions) has been injured, and the Heart must be regulated first. The same applies to the fifth and seventh months, except that miscarriage in the first month is generally unknown to people. The first month corresponds to the Liver. Anger often leads to miscarriage, and washing the lower body opens the orifices, which can also cause miscarriage. Once a miscarriage has occurred, the Liver Meridian is injured, making subsequent pregnancies prone to miscarriage. Most of those currently childless have suffered from miscarriage in the first month; they are not necessarily infertile. Therefore, after initial intercourse, one should best rest and recuperate, avoid further sexual intercourse to disturb the Uterus, avoid fatigue and anger, avoid lifting heavy objects, avoid bathing, and frequently take herbs to nourish the Liver and calm Qi, so that the Fetus will be secure.
Sun Simiao in *Qianjin Fang* stated: For any woman who suffers miscarriage after three months of pregnancy, although there may be insufficient Qi and Blood, it is primarily due to injury to the Zhongchong Mai (i.e., the Stomach Meridian of Foot-Yangming, which supplies nutrition for pregnancy). At this stage, one must regulate diet, abstain from sexual desire, and guard against anger, thereby avoiding the disaster of miscarriage.
Pan Shuofu stated: Chao's theory discusses how various meridians nourish the Fetus, each for thirty days. Among the Twelve Regular Meridians, only the Heart and Small Intestine do not directly nourish the Fetus. Why? The Heart is a Yang Zang organ (Mu Zang), and the Small Intestine is a Fu organ, primarily responsible for generating Blood and connecting with the vessels. The Classics state that "the true Qi of the Zang organs communicates with the Heart," and the Heart stores the Qi of the blood vessels. During pregnancy, the flow of meridians is obstructed, as Scholar Xu described: closing the menstruation to nourish the Fetus. Thus, we know that the Fetus is based on Blood, and its entire process concerns the Heart; therefore, it is inappropriate to distribute nourishment sequentially among the meridians. In the third month of pregnancy, the Pericardium (the protective outer layer and meridian surrounding the Heart) nourishes the Fetus. *Ling Shu* states that the Pericardium governs the function of the vessels. If Qi and Blood are diverted to nourish the Fetus, the pulse will inevitably appear deficient and intermittent. The Classics say "the Heart harmonizes with the vessels." Although the Heart and Pericardium are divided into two meridians, they essentially belong to the same Zang organ. If, at the appointed time for a specific meridian to nourish the Fetus, that meridian's deficiency and excess are unregulated, the Fetus will become unstable, and in severe cases, vaginal bleeding and miscarriage will occur.