Development and internalization of the constitutional entities (members) of the human being in pregnancy

Below, we attempt to draw an integrated picture of the embryonic/foetal stages of human development that includes all aspects of human bodily development, based on Rudolf Steiner’s study of the human being and taking into consideration research on embryology and child development (1). Anthroposophic Medicine refers to the “Wesensglieder” (this word has been translated into English as “constitutional members or entities”) of the human being. In this translation we use the term “constitutional entities” in order to make it clear that these four aspects of the human being are distinct, equally (ontologically) real, and interwoven throughout our lives (2, p. 7–22). This may be relevant for pregnancy management and obstetrics.

Conception

From a physical perspective, human conception has been researched in detail. Both the sperm, which quickly advances through the uterus into the fallopian tubes after ejaculation, and the egg cell, which has been released through ovulation, represent “sex cells that are differentiated in an extremely one-sided way and are effectively dying” (3, p. 27); the egg cell’s survival period in the absence of fertilization is only 24–36 hours. The zygote, in contrast, is the “origin of the new individual, in which (potentially) everything is contained that constitutes the future organism. Nothing more is added. The zygote is (functionally) already complete. Further development then takes place through partitioning, not through the addition of single cells in the way that we build a house by laying one stone on top of another. Even though nothing “human” can be seen (outwardly) in the zygote, the whole is already (functionally) present and already shows its enormous potential in the first developmental steps.” (3, p. 27).

Each of us can ask ourselves: Who begot me? And we can deepen this question when we ask not only about the origins of our physical appearance but about the origins of our I, our individuality. Did my parents “make me”? Parents with a large number of children automatically notice from the beginning how different these children are from each other. In cultural and religious history, belief in the reincarnation of human individuals is older than the New Testament, and with it the idea that human individuality is not begot by our biological parents but rather manifests a much longer history. It can explain the roots of the striking individuality of each person regardless of all bodily, emotional and social circumstances. Many people worldwide and in Germany share this conviction.

Development of the embryonic sheaths

In a remarkable accordance with the Rhythm of the Week, which also informs the creation story of Genesis, the fertilized egg changes throughout its journey into the uterus and begins to implant itself in the uterus wall on the 6th day. Full implantation of the embryo is completed on the 7th day. The human embryo is particularly intimately connected with the maternal organism, and is completely imbedded in the endometrium (interstitial nidation), which is unique to humans and not even the case in primates. The embryo’s second week of life is characterized by intensive, all-round development of the embryonic sheaths, with an “initially rather restrained, virtually centripetal developmental tendency on the part of the embryoblast, from which the future embryo develops” (3, p. 29). In the second week, the embryo’s structure differentiates into a “top” (epiblast) and “bottom” (hypoblast). The yolk sac and the allantois derive from the latter, the amnion from the former. The activity of early embryonic growth is highly peripherally oriented, and because of the human embryo’s complete nidation and its outer sheath, the chorion, it is more intimately and fully connected with the maternal organism than is the case in any other species. The concept of “bonding” shows an immediately tangible physiological meaning in this context. And in this context, the embryo (trophoblast) first develops the body parts that it will lose at physical birth, but which initially take over “all organ functions of the embryo” (3, p. 29): the embryonic sheaths.

The embryo forms a total of “four sets of membranes” (4, p. 501):

The yolk sac , which everts from the lower blastodermic layer of the embryo (hypoblast, embryonic endoderm), also plays a role in the transfer of nutrients for humans in the 2nd and 3rd weeks of gestation. Beginning in the 3rd gestation week (GW), haematopoiesis begins within it, before moving into the embryo. The yolk sac contributes to the bowel anlage, and the progametes that separated out very early also remain within its wall before they migrate into the gonadal anlage (5, p. 158) and form the foundation for conceiving a physical descendant.

The amnion originates in the upper blastodermic layer of the embryo (epiblast, embryonic ectoderm) and surrounds the embryo as a transparent but firm sheath. In general, it creates weightless, ocean-like, free-floating conditions for the primary development of terrestrial vertebrate embryos. The clear amniotic fluid is similar in composition to cerebrospinal fluid (which is identical before it is closed off from the amniotic cavity). It enables uniform warming of the embryo “in a water bath”, symmetrical growth, and especially the spherical rounding of the head. It also enables foetal lung development, and contributes to the maintenance of fluid homoeostasis (5, p. 157). Normal foetal growth remains dependent on the intact function of the amnion until birth. Its importance in the phenomenon of scar-free wound healing during the first two trimesters of gestation is also therapeutically interesting (6, p. 71–73); it protects the foetus from injuries and is itself not infrequently the object of an iatrogenic lesion (amniocentesis).

The allantois forms “below and behind”, in the region where the urinary bladder will later be located, and in humans it everts into the mesenchyme of the body stalk, which connects the embryo with the outermost blastodermic layer, the chorion.
In birds and reptiles, the allantois stores urinary excretions—protein metabolism waste that contains nitrogen and is potentially toxic—in the form of a stretching, extra-embryonic urinary bladder. In chicken embryos, for example, the allantois vessels enable respiration. The allantois sticks to the inner surface of the chorion, causing a strong vascularization of the sheath generated in this way. This enables an exchange of gases through the porous eggshell (as well as calcium absorption from the shell), and in this way the embryo’s respiration is maintained by this extra-embryonic organ.
In humans, these functions are metamorphosed in that the vascularization of the umbilicus and placenta originate in the allantois (chorioallantoid placenta formation in humans), essentially stabilizing the body stalk and umbilicus which stem from it and enabling its central function. The flexible umbilicus, which connects the centre and the periphery of the embryo and which facilitates respiration and excretion, among other things, is therefore the remaining form of the allantois as third embryonic sheath (7). Its freedom of movement and function is made possible by the amniotic fluid.

The chorion surrounds the embryo and its other sheaths on all sides and quickly protrudes into the maternal uterine tissue – further, to our current knowledge, than in any animal’s placentation (8, p. 39): “The deep invasion appears to be a uniquely human phenomenon among higher primates and challenges our perception of the physical extent of the placenta“ (9). In doing so, it radically changes its form. First, primary villi push through in all directions into cavities, that fill with the mother’s blood. At the end of the embryonic organ anlage formation period, in the 8th week of gestation and the transition into the foetal period, the placenta essentially discontinues its growth and limits the total villi layer to the decidual plate. Though the mass of the chorion initially significantly outweighs the embryo, the weight of the placenta at birth weighs only approximately one seventh of the foetal weight (500g).

Universal function of the placenta in pregnancy

Initially, the placenta regulates the warmth of the embryo (3, p. 38) (10, p. 202), which is approximately 0.5°C warmer than the mother’s body temperature, and also appears to inhibit the foetus’ generation of its own heat through its brown adipose tissue before birth. Along with the umbilical circulation, it allows for the outflow of metabolic heat from the foetus, and has an equalizing – literally a “tempering” – effect on the foetal temperature (11, 12). The placenta regulates oxygenation, which slowly increases (9), and facilitates the excretion of metabolic end products. It protects the embryo from infections, and also develops a bacterial microbiome during gestation which, astonishingly, most closely resembles the microbiome of the maternal oral cavity (13) and which plays a significant role in immunological maturation. The connection between maternal periodontal disease and premature parturition has been known empirically for quite some time (13, 14), so dental care is especially important during pregnancy.

The placenta forms more than 100 different active endocrine peptides and hormones, which also alter the maternal organism and help to regulate uterine blood flow. In so doing, the placental hormone production interweaves with that of the foetus: The hormone DHEA-S, which is originally produced by the foetal adrenal cortex (15), is converted by the placenta into oestrogen, which maintains the increased uterine perfusion in the maternal organism. This stabilizes the foeto-maternal unit (16). The placenta has a strong regulating influence on the pituitary-adrenal-axis of the mother and the foetus, because it secretes corticotropin-releasing hormone (CRH) especially into the maternal but also into the foetal organism, which stimulates cortisol formation in the adrenal cortex. At the same time, it limits its effects until shortly before birth with a corresponding binding protein (CRHBP). Placental CRH production only occurs in primates. It is important to be aware that the placenta is a foetal organ. The hormonal cascade that sets normal, healthy human birth in motion begins with an increase in placental CRH and a decrease in CRHBP (17).

During gestation, the placenta takes on the function of a peripheral heart, which has already been described by de Langen (18) and was summarized by Schad as follows: “Venous reflux, on the other hand, takes place in the foetal and the maternal circulatory systems through the rhythmic, peristaltic contractions and dilations of the child’s placental terminal villi, […] purely through the sum of all placental capillaries on the child’s end. The terminal villi expand and contract to twice and half their length, respectively, in the maternal blood.” (8, p. 14–15) It is also of note that the embryonic heart is itself formed extra-embryonically in the 3rd GW (before the formation of the head anlage) and is incorporated into the embryo in the 4th GW (3, p. 74). Finally, the placenta’s metabolic function of nourishing the embryo is vitally important, in addition to the extremely important exchange and transport of maternal nourishment. The boundary, or “interface” of the child’s portion and the maternal portion of the placenta is not easy to determine, since, for example, large numbers of exosomes are released from the placenta into the maternal circulation (highly stable nanovesicles), significantly influencing the maternal physiology (9). From this perspective, the embryo permeates the entire maternal organism through the placenta. Disturbances of this process of permeation, which can also be seen as a dialogue between the maternal organism and that of the child, can cause gestosis.

The placenta contains no nervous system and does not ossify, physiologically, while the development of the head, the sensory organs and the nervous system appear to be especially prominent in the embryo – an image that can be meditated on in terms of “point and periphery”. The placenta can also remain vital if the embryo dies (blighted ovum). 

After describing the embryonic sheaths and especially the placenta, Rohen and Lütjen-Drecoll draw an initial conclusion that is significant in this context: “At this point, the entire organism with its future life processes is already functionally alive, not in single organs, but in the environment, so to speak, and without organic differentiations. […] From this perspective, we could describe the subsequent embryo formation as a largely structured “functional involution” or inversion into a bodily interior, in which the initially diffusely spread “spheres” of processes then develop into individual organs. Indeed, we also see that the placenta is increasingly broken down as the corresponding organs within the embryo develop and become functional. Therefore, birth must take place at the point at which all functional processes have, in principle, transferred to the foetus (have basically been inverted) and, in so doing, have “vacated” their surroundings. At this point, the placenta as site of primary organ processes has become superfluous.” (3, p. 38)

From this, it is apparent that the remainder of gestation can be understood physiologically as a process of internalization from the surroundings in which the nascent child begins to develop its life activity. We describe these processes in some detail because they represent a very precise image or model of what takes place on higher levels of human existence after birth, in childhood. Indeed, we can describe the child as a being that in its key functions is not autonomous, but rather dependent on a self-determined, vital connection with its surroundings, a being that through a primarily self-determined connection (nidation, bond) with its surroundings gradually internalizes functions (and develops, in the process, its inner differentiation). This continues until, in the process of a crisis of separation or “birth”, it detaches itself from the human surroundings on which it had hitherto been essentially dependent and becomes an autonomous, individual adult, unique in its inner independence and freedom as compared to the animal kingdom. Our theory is that what can be seen physically in embryonic development takes place in the form of further “births” on different levels of the human being up until the “birth of the I” at the end of adolescence.

The embryonic sheaths and the constitutional entities of the human being

Rudolf Steiner, the founder of Anthroposophic Medicine, focuses on four systems in a foundational lecture on Anthroposophic Medicine from October 27, 1922: “a physically organized system, an etherically organized system, […] an astrally organized system and that which [characterizes] the human being – a true I-system”. Later in the lecture, Steiner discusses the renal system, among other things, in more detail and says: “[…] in order to understand the whole of human development, we would need to study the attached organs during embryonic development much more precisely than the processes which arise from the splitting of the gametes” (19, p. 112), and he immediately proceeds to name the “allantois and amnion” as an example. If we follow the characteristic style of this lecture, the question arises whether Steiner sees “direct physical representation of these four systems in the four embryonic sheaths” (7, p. 28), which are no longer perceptible in their full and immediate reality after birth and the loss of the embryonic sheaths, with the exception of the physical body. If physicians and medical students devote themselves to the embryonic sheaths, can they, in the most intimate way possible, dedicate their attention to an immediate view of what Anthroposophic Medicine refers to as the higher constitutional entities of the human being? In 1924, Steiner formulates it baldly: “We must know that the amnion is the physical correlate of the etheric body, the allantois is the physical correlate of the astral body, the chorion is the physical correlate of the I organization […]” (19, p. 308). Here, he mentions the original anlagen of the embryonic sheaths (allantois, chorion), not the organs which derive from them, such as the umbilicus and the placenta (7). The yolk sac is not mentioned.

As described in the last section, modern embryology confirms the significance of the embryonic sheaths that R. Steiner emphasizes. To summarize:

The yolk sac is closely connected to the physical aspect of the body (nutrition, heredity). In the evolution of vertebrates, it represents the only extra-embryonic sheath in fish. Its function is already completely internalized in utero, while all of the other three sheaths or their derivatives continue (extra-embryonic/extra-foetal) functioning until birth.

The amnion can be addressed as the “life-bearing” sheath of the embryo. Its central function is to contain the amniotic fluid. It almost completely cancels out the gravity of the earth. Life is dependent on water, and is characterized by its ability to overcome gravity (as seen in the circulation of all plants). The amnion’s relationship to the human life organization, the etheric body, is an obvious conclusion. All terrestrial vertebrates beginning with the class of reptiles develop an amnion and an allantois.

The derivates of the allantois – the umbilicus (vessels) and (parts of) the urinary bladder – are clearly connected to the animal soul organization of the human being, called the astral body in anthroposophy. Excretion and respiration are already central characteristics of ensouled organisms. The nitrogen relationship is striking in the evolutionary development of this organ (16), as it plays an important role in reptiles and birds, and in pigs even has a large extension in the form of an extra-embryonic bladder (“sausage bladder”). The internalization of nitrogen in the form of animal protein (which contains 16% nitrogen) and numerous nitrogen-rich hormones (including adrenaline, ACTH) is closely connected to mobility (muscle proteins) and consciousness. The renal activity connected with nitrogen excretion has a parallel activity rhythm to that of consciousness and movement. The relationship of nitrogen to air (the atmosphere contains 99% of the total nitrogen on earth – a remarkably “extra-terrestrial” concentration of the entities that constitute the earth) and finally the characteristics of nitrogen in relation to the formation of toxins (alkaloids, potassium cyanide) and controversial technical uses (from fertilizer to dynamite) show a very characteristic profile: tension, ambivalence, but also an inner life of feelings and drives are connected with these qualities.

The chorion and the placenta originating from it undoubtedly represent the primary sheath organ in human embryonic and foetal development, which simultaneously realizes the connection to the mother and also takes on the leading role. The placenta integrates embryonic physiology extra-embryonically and combines the foetus and the maternal organism into a foeto-maternal unit. It is remarkably different from a priori fixed placenta forms in mammals, and “during the first three months, [it traverses] equally all stages from general to centred placentation” (8, p. 59). The relationship to warmth can already be clearly seen in that the formation of the placenta is specific to the class of animals that can assimilate embryonic-foetal growth inside a homoeothermically regulated body and is especially close to human beings: mammals. Schad and Brettschneider have described the placental development in mammals and humans mentioned here in unique detail and clarity (20, p. 705–820). Human-specific characteristics of human placentation are mentioned several times above.

If we recognize that the placenta is of paramount importance for the formation of the human embryo as well as for the human-specific embodiment of the foeto-maternal dialogue, R. Steiner’s indication regarding the correlation between this organ and the I organization is very logical to an open mind. In terms of the interaction of the I, astral body, etheric body and physical body, we can also see from this observation that the constitutional entities of the unborn child build upon each other in their interactions. Proceeding from the placenta, and thereby from the I organization connected with it, the umbilicus communicates within the polarity of periphery and centre, the amnion surrounds and carries the life processes of the embryo, whose physical body (which soon absorbs the yolk sac derivates) is nourished by the sheaths and physically articulates itself into finely differentiated structures, all the way to the gradual calcium build-up of bones and teeth. After birth, we will also encounter other forms of interaction between the constitutional entities.

The individuality of the unborn

However, we must first ask: How exactly do the I, I organization, and the presence of the I manifest in the embryonic period? Does the embryo even “have” an I? Human embryology also speaks of embryonic “individuation”, referring to a specific occurrence in the middle of the 3rd week of gestation. In this week, the development of a third kind of original embryonic tissue (the mesoderm, between the ectoderm and the endoderm) determines the formation of the bodily axis as well as the front and the back. Approximately in the middle of the blastodermic layer, endoderm and ectoderm merge into a stripe-shaped section (primitive streak). From the “forward”-streaming cell current in this region between the ectoderm and the endoderm, the anlage of the chorda dorsalis, the spinal process, is generated. “For the first time, the embryonic material is now oriented toward a future bodily form. With the formation of a spinal process, it is now […] decided that an individual will arise from the thus far developed embryo.” (21, S. 133) This “individuation” of the embryo occurs on the 17th day of pregnancy; after this point, twins can no longer form. The chorda dorsalis becomes the point of origin of crucial further formation processes in the human body. The nucleus pulposus of the intervertebral discs derives directly from the chorda. The chorda can be seen as the initial anlage of the spine and of the human capacity for uprightness (22).

From the perspective of anthroposophy, the human I is a spiritual reality that is not begot by the parents of the child and that does not dissolve with the death of the organism. “The human I-being is predisposed to development. […] For Anthroposophic Medicine, this development is inseparably tied to repeated earthly lives” (2, p. 15). The human being is regarded as an incarnating, developing individual with a different origin than the physical “model body” it inherits from its parents (23) (in-depth analysis of the primary sources by R. Steiner in 24, p. 99–141]. According to his spiritual-scientific research as recorded in many sections of his lectures, R. Steiner spoke out on this topic as follows: “In the first days after fertilization […] the spiritual individual who is coming down does not yet act upon the development of the physical human being, but it is […] already connected with the developing embryo. It takes hold approximately from the 18th, 19th, 20th, and 21st days after fertilization; then, that which has come down from a higher world begins to work on the developing human being.” (25, p. 201) see also (24, S. 137–139).

This reveals a striking correspondence between Steiner’s purely spiritual-scientific research results and the current state of embryological research, in that we can only speak of a truly individual (literally: not able to be divided) development of the body from the 17th day post-conception onwards. At this point, Anthroposophic Medicine is of the perspective that the human individual springs from a soul-spiritual seed that has already passed through former earthly lives and therefore former individuation processes, which decisively imprints upon the body-related I organization, soul organization and life organization, and which unites with the physical body inherited from the parents in the second half of the third week of pregnancy. We can see this as a sort of “second conception” and be reminded of the words from the Gospel of Luke on the Jordan Baptism quoted at the beginning of this text in the sense that now, for the first time, the determining spiritual individual becomes active in the development of the body. If we follow this perspective, the human individual is already fully present and creatively active in the body after this point, though the child is completely unconscious of it. Connected to this is the statement that the pre-birth, “pre-earthly” I of the child is active in the maternal organism, and changes it – and the mother can certainly be fully conscious of this activity or at least feel it. Whether the mother regards the experience of pregnancy as “only” physiological or whether she comprehends it as a real, bodily encounter between two individuals makes a crucial difference. It is very probable that the way the mother thinks about her pregnancy has a significant influence on her experience and potentially on which complaints she develops, but also on what solutions she can access – such as inner dialogue with the unborn child, which can prove to be a therapeutically important gateway.

What does it mean if, as described above, the placenta is seen as the primary organ during the embryonic period for the engagement of the unborn child’s I organization?
Can such a perspective be a corrective for the view of the human I that is permeated with the psychological ego in societies with western lifestyles? Obviously, the unconscious, body-forming I has little to do with this view. In fact, we might dare to theorize that the psychological ego is a phenomenon that can claim reality only between birth and death, but neither before or after – and in this sense, quite in line with the Buddhist worldview, represents an illusory consciousness that meditation seeks to overcome.

The ego suffers from its estrangement from the world. “It easily withdraws into itself. It thinks, imagines, plans, expects much according to its self-designed concepts. […] Steiner describes the higher I as open to the world, even merged with the world. It knows, to quote Goethe, that it has the world to thank for itself. […] The self-serving I experiences itself as centric, or in extreme cases egocentric. The true I is pure interest in the world, and lives its openness toward the world; it is the social I that is capable of comprehending ‘you’. This dual I concept for human beings can now be a paradigm for a closer understanding of human embryonic processes. […] On the one hand we find the formation of biological interiors with individual organs that work separately from each other in the embryo; on the other hand, we find the openness to the environment of the universal embryonic sheath organs. Both of these are the child’s tissue. In this way, the human organism presents itself altogether in a dual fashion before birth, containing both openness and self-centeredness. And in this it is a more complete embodiment of both human gestures than it is after birth.” (8, p. 71–72) However, the path toward freedom and autonomy necessarily requires us to shed the sheath organs: “Before birth, the sheath organization is more autonomous than the child. […]  After birth, on the other hand, the child is more autonomous than the sheath organs.” (8, p. 55) We will encounter this step again on higher levels after birth, as well.

We modern human beings tend to see our brain as our central organ (even though, if asked to point to ourselves, we generally point to our chest and not our forehead). The nerve-free, formatively active placenta, in substantial exchange and conjoined with its surroundings, represents a very different “house of the I” than the cerebrum. Contemplating the embryonic sheaths in this way can be very meaningful for physicians and for parents.

One last perspective, also presented in detail by Schad, should be added here: the human embryo is the most carefully concealed, enveloped embryo of all species (its complete nidation in the uterine tissue was already mentioned above). In the course of evolution, sheath formation has become more and more complex, from the simple frog egg, to the sauropod egg, all the way to human gestation. What does it mean that within the framework of prenatal diagnostics this sheath formation is more and more radically eliminated? If we assume an actually present I in the embryo and its sheaths, what is the significance of ultrasound or amniocentesis diagnostics? Especially as the I perceives not only facts but especially intentions? To design prenatal medicine in a manner that fully takes into account the human dignity of everyone involved is an important desideratum. For we know, today, that unborn children reflect the soul experiences of their environment to an extremely significant extent – whether it is maternal stress or other influences that can potentially permanently disturb the sensitive embryonic bodily formation processes, such as brain formation (for more detail, see 16).

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