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Voices Online Edition
Vol. XXIV, No. 2
Pentecost 2009

Women for Faith & Family
Celebrating 25 years of service to the Church

Embryonic Dialogues

by Kathleen Curran Sweeney

“There is a renewed understanding that the ‘I’ is constituted in relation to the ‘thou’ and that the two mutually interpenetrate.”

Joseph Cardinal Ratzinger
in Called to Communion, 1996

In the earliest contact between a human mother and her embryonic child, immediately after conception, a unique communication system is established. The marvelous intricacy of what happens every time a child is conceived is truly impressive. It is revealing to explore this early relationship in some detail. What follows is a partial summary of embryology and fetology, and how this reflects Christian Trinitarian theology.

Every human being begins life in a relationship to God as a creature, and to a particular mother and father as their child. These relationships are permanent and also challenging. They depend on very intense communication.

It is important to remember that in every pregnancy there are three human persons, the mother, father and child, interrelating from the beginning — an interdependent trio evidencing the fruit of love communicated through the body. While the relationship of mother and child is the most obvious in pregnancy, the father is always present from the first moment of conception, begetting in the child his genetic inheritance forward to a new generation. His emotional, spiritual and material support of the mother and child, or the absence thereof, has a powerful effect on the well-being of mother and child.

Every mother-father-child trio is called to image the love and unity of the Divine Trinity. According to Saint Thomas Aquinas: “the birth of the Son from the Father is the origin of every begetting of another”.1 A man’s fatherhood, in imitation of God’s fatherhood, is his highest calling. Moreover, the child from the moment of conception is a concrete expression of the unity, communion and love of the father and the mother, reflecting, by analogy, the Holy Spirit, who is the unity, communion and love of the Father and Son. As we focus on the biological interrelating of mother and child, the Trinitarian reality that includes the father’s relationship to them must not be forgotten.

In his Letter to Families, Pope John Paul II wrote:

The divine “We” is the eternal pattern of the human “we” especially of that “we” formed by the man and the woman created in the divine image and likeness…. While always acknowledging the absolute transcendence of the Creator with regard to His creatures, we can see the family’s ultimate relationship to the divine “We”.… In the family thus constituted there appears a new unity, in which the relationship “of communion” between the parents attains complete fulfillment…. The Second Vatican Council … refers not only to the divine image and likeness which every human being as such already possesses, but also and primarily to “a certain similarity between the union of the divine persons and the union of God’s children in truth and love”. (Gaudium et spes 24) … In the words of the Council, the “communion” of persons is drawn in a certain sense from the mystery of the Trinitarian “We” and therefore “conjugal communion” also refers to the mystery.  The family, which originates in the love of man and woman, ultimately derives from the mystery of God. (Letter to Families, 1994, 6-8)

“Peace begins in the womb”, reads a bumper sticker produced by Feminists for Life. How true this is, from many perspectives! But not without overcoming potential conflict between mother and child. This begins as a great drama from the first moment of conception.

A dialogue between the one-cell embryo (zygote) and the mother starts up from day one of pregnancy. These are two separate human organisms with genetic differences, distinct physical needs and goals. The primary goal of the embryo is to grow and develop normally and healthily. The physical goal of the mother is to monitor the new challenge to her system, assess the viability of the embryo and, hopefully a personal goal is to accept hospitably her new guest who is so dependent upon her. The potential for conflict is real. Yet this conflict has its own intrinsic “peace plan”.

A woman’s immune system will normally reject any alien cells that her system does not recognize as her own. Why does it not reject the embryo, whose cells contain genetic information from the father as well as from her own inheritance — cells of a distinct human being with its own unique DNA? This has presented something of a mystery to biological researchers. Only partial understanding of this earliest human relationship is currently available. It is an amazingly complex reality. Should it surprise us that God’s most cherished and magnificent creation, a new unique human person, should begin existence in an intensely complex activity of interdependent and mutually supportive communication?

Conflict resolution…

The action of this story of “conflict resolution” begins shortly after fertilization. To overcome the fact that the embryo is antigenically alien to the mother, the maternal immune system must be suppressed without endangering the life of the mother. Although in the past it was thought that the embryo is passive and silent in the beginning of pregnancy, research has revealed that in the first hours of its existence, the embryo plays an active role both on behalf of the mother and for its own growth.

Critical in this interaction is what is known as “early pregnancy factor” (EPF), a protein (homologue of chaperonin 10, or cpn10) that acts as a suppressant of the mother’s immune system and as a factor in the embryo’s growth and well-being. (The embryo produces “ovum factor”, which, together with prolactin, induces the ovaries to produce EPF.) EPF is stimulated when primary embryonic cells are actively dividing and appears within six to twenty-four hours of fertilization.2

EPF production has a role in the growth and survival of the human fetus throughout the pregnancy. During the first three days of embryonic development, global changes in gene expression, involving more than 8300 genes, occur. The production of EPF is essential to a sequence of events necessary for DNA synthesis and cell division. EPF stimulates secretions of endocrine cells (which produce hormones) into surrounding tissue during the early development of the embryo, which regulates maternal reaction against the presence of the embryo, acting as an immunosuppressant.

Thus, a biochemical communication network is set up between embryo and mother, which both protects the mother and enables successful growth of the embryo.

It is now understood that the maternal system recognizes the presence of her preborn child before implantation. This points to the critical nature of the mother-embryo relating in this earliest period of embryo development within the mother’s body.

A test for the presence of EPF can be used for early pregnancy detection. Later EPF also prepares the mother’s immune system for the implantation of the embryo.3 At the blastocyst stage of embryo development, the embryo can directly produce EPF, which continues to contribute to the embryo’s development after implantation.4

Successful implantation of the embryo in the endometrium of the mother’s uterus requires both receptivity by the mother’s endometrium and the embryo’s active molecular contribution.

In the implantation process, there are three phases: 1) positioning of the embryo in a particular orientation toward the endometrium; 2) attachment to the endometrium; and 3) entry. The timing of this process is critical. The endometrium is receptive for six to eight days after ovulation, and remains receptive for four days — a period known as the “implantation window”.

If fertilization is delayed and out of phase with the uterus, the necessary communication may fail to occur and the embryo will be lost. Embryo loss can also occur if the embryonic signals are weak or lacking and the uterus does not respond in a way that enables the pregnancy to continue. If there is delayed maturity of the egg resulting in poor embryonic development, or impairment in uterine receptivity or in the “dialogue” between the embryo and the uterus, the embryo can fail to implant.

The embryo’s role in the modulation of the endocrine activity during endometrial implantation involves regulating the production of soluble factors that facilitate the embryo’s entry into the endometrium. (Progesterone, estrogen, lactogen and human chorionic gonadotropin [hCG] are the most common hormones active in pregnancy.)

Endocrine action can cross over the interface between maternal and embryonic systems and directly influence the systemic physiological changes involved. Besides the hormones progesterone and estrogen, which, in complex interactions, induce the endometrial changes needed for implantation, androgen receptors and testosterones are involved as well in the changes in endometrial function. The other important factor in endometrial receptivity, hCG, produced by the embryonic trophoblast, has an immunosuppressive role and stimulates progesterone. There are high concentrations of hCG in the first three months of pregnancy.

The trophoblast, the outermost layer of the embryo, sends biochemical signals to the endometrium to gain access to the mother’s circulation system. The embryo needs to obtain oxygen from the mother’s blood in the uterus. To meet this need of the embryo, numerous factors and functions must be marshaled. Intercellular messengers, the cytokines participate in complex signaling networks — signals from both the embryo and the mother. (Cytokines are signaling molecules similar to hormones.) Numerous different factors at the level of gene regulation and protein expression are involved, and these have multiple functions.5

During the implantation process, differentiation occurs in the embryonic trophoblast, which has an important role in the dialogue between maternal and embryonic systems.

In the trophoblast, particular cells proliferate to penetrate the endometrium and grow toward oxygen. These cells then differentiate into other cells, which form lacunae (spaces) that can fill with maternal blood. The trophoblast will form the placenta for the embryo. It also secretes the hCG hormone that maintains the corpus luteum — a temporary endocrine structure that produces estrogens and progesterone needed to maintain pregnancy — and thereby the thickened uterine lining, and secretes progesterone and placental lactogen, which prepares the mammary glands for milk production.

Thus, besides inhibiting immune rejection by the mother, the embryo is the source of several functions important to the mother-child relationship.

Embryo interacts with its mother’s system

The entry of the embryo into the endometrium is often described as “invasion”. But I wonder if this terminology might encourage the attitude of some pro-abortion propaganda that considers the human embryo to be a kind of parasite on the mother that she is justified in rejecting?6 This term contrasts with the mutuality of the interaction between the mother’s system and the embryo. We should not forget that this reality was initiated by the “invasion” of a woman’s body in sexual intercourse, which resulted in the “invasion” of a male sperm into the woman’s egg.

All of these realities can also be described in terms of the mutual interaction of love, which is naturally both giving of oneself and receiving from another who is beloved. We can, therefore, be justified in describing this beautiful interaction between a mother and her child happening at the earliest beginning of their relationship, as the mutual receptivity and gift that is the fruit of the exchange of love between man and woman. This language highlights the fact that a strong committed love of spouses is the appropriate origin of human conception.

Remaining cells protect the mother

A fascinating aspect of the biological relationship between a mother and her child is the phenomenon of microchimerism: cells from the child remain in the mother’s body for years after the pregnancy, perhaps permanently, and cells from the mother remain in the child. This may have beneficial effects.

Breast cancer research has found that “fetal microchimerism was found significantly more often in healthy women than in women with breast cancer (43% versus 14% respectively)”.7

Researchers indicate that these cells may put the woman’s immune system on alert for malignant cells to destroy. Fetal microchimerism may provide risk-reduction for recurring malignancy in hematopoietic cell transplantation (HCT). (HCT is a treatment for a variety of disorders through blood cell transfer; for example, bone marrow and umbilical cord blood transplants.)

A woman who has borne several children may be tolerant of paternal antigens and therefore may be a potential HCT donor for her children. In addition, maternal cells that persist in a child may be helpful in sibling blood donation. (However, these cells are also implicated in autoimmune diseases and possibly in chronic graft-versus-host disease [GVHD]. Much is still unknown about this phenomenon.)

Other “intercommunication” factors

Although many people are now more aware of the relationship between a mother and the child in her womb at later stages of pregnancy, I would like here to note some experiences that further emphasize the nature of the dialogue and relationality of the mother and unborn child, and also the role of the child’s father. Dr. Thomas Verny has brought together a variety of studies of this relationship in his book The Secret Life of the Unborn Child.8

We have seen already how complex the biochemical interdependence is in this relationship. The mother and child have separate neurological and blood circulation systems so neurohormonal links are the way in which emotions are communicated between them. Fear and anxiety arousal, for example, flow through the bloodstream. In particular, a mother’s unresolved personal stress increases maternal neurohormonal production and significantly alters the fetal body mechanisms. Unborn babies sense a mother’s distress almost immediately.

Positive emotions also affect the child. Adrenaline, serotonin and oxytocin will cross the fetal placenta and affect the unborn child. By the fifth week, a fetus exhibits complex reflex actions that express his reaction to circumstances both external and internal to the womb. By the eighth week, he expresses likes and dislikes by moving his arms, legs, head and trunk. In his fourth month, he is frowning and grimacing. It has become common knowledge that unborn children react positively or negatively to music their mother is listening to, and that her voice is familiar to him — and the father’s voice as well.

What is particularly fascinating is what appears to be “extrasensory communication” between a mother and her unborn child — knowledge that does not have any apparent material basis.

How does the child sense love and acceptance in the mother? How can he know her thoughts and feelings? Four centuries ago, Leonardo da Vinci recognized this reality: “the things desired by the mother are often found impressed on the child which the mother carries at the time of the desire....” Medical science has only recently caught up with this insight, since it has been mainly concerned with ridding itself of superstition, and scientists have often been suspicious of anything that could not be observed under a microscope. It was not until the mid-20th century that studies verified such communication between a mother and her unborn child.

Emotional influences on physiology

Dr. Monika Lukesch, a German psychologist, found in a study of two thousand women that a mother’s attitude toward her unborn child was the single greatest influence on how the infant turned out: “The children of accepting mothers, who looked forward to having a family, were much healthier, emotionally and physically, at birth and afterward, than the offspring of rejecting mothers”.9

Another study indicated that the unborn children of women who were ambivalent — outwardly happy about their pregnancies, but inwardly negative — somehow sensed this ambivalence, even though husbands and friends did not, and the child subsequently often had behavioral and gastrointestinal problems.

Ambivalence is a complex and subtle emotion that does not seem to be connected with a physiological state, and can be so muted that the woman herself is not aware of it. Some form of sympathetic communication to the child apparently occurs and the child’s emotional radar is so finely tuned that he picks up even the slightest of maternal emotions.

Also, the unborn children of mothers who were not pleased about having a child seemed to receive a mixed message and appeared confused, apathetic and lethargic after birth. “Nothing we know about the human body can explain why these feelings affect the unborn child”, Dr. Verny comments.10 This communication occurs beyond physiological and behavioral connections and seems to be a kind of sympathetic response similar to what we experience in intuition.

Some striking stories of dreams suggest the unborn child can communicate to the mother in a dream she experiences. One doctor reported that a woman who suffered a miscarriage had the night before shouted herself awake several times by crying out, “I want out, let me out.” She felt certain her child was speaking through her. Another mother had a dream at the beginning of the third trimester that she was about to go into labor, and then did in fact give birth prematurely two weeks later, even though there had been no complications in her pregnancy. Although the mechanisms behind these dream communications are unknown, some believe they are a kind of extrasensory communication from the child.11

In addition, the woman’s relationship to the father has a distinct effect on the happiness and security communicated to her child in the womb. A mother needs the emotional support of the father to be free to fully give herself lovingly to the child. It has become clear that a strong, loving and nurturing bond between the mother and her unborn child can protect the child from even very traumatic shocks.12

Forming the “I-Thou” relationship

Many studies have been done about mother-child bonding after birth, and more recently it has been realized that this bonding begins in utero. When a positive bond has been developed while the mother carries the child in her womb, post-birth bonding feels very natural to both mother and child. But there is also more bonding going on with the father than has been realized in the past. In the classic experiment of observing babies’ reactions when a mother or father left the room, one investigator noticed that “a father’s leave-taking upset an infant as much as his mother’s did”.13 It should be emphasized, however, that neither prenatal nor postnatal experiences are the source of an absolute determinism for a person. They can create a predisposition but are not the whole story of a child’s life.

These realities reveal important facts that are constitutive of human life from its very beginning of conception in the womb.

First, it makes clear that the human embryo, even as a one-cell zygote, is an individual human subject with his/her own personal needs, drives and contributions that call for respect.

Secondly, it shows us that the I-Thou relationship of a mother and child begins at conception, is very complex and is mutually influential throughout the lives of each. The human body is an expression of the human spirit.

In the physiological relationship of a mother with her embryo, we see a paradigm of human life: the gift of self to another is an enriching, creative, developmental and mutually beneficial act for which our bodies have a natural aptitude. It takes a spiritual/psychological act of rebellion against nature to destroy this innate tendency we have for self-gift. When we recognize the Creator’s goodness reflected in natural phenomena, we are open to cooperation with His plan for life. At the basis of all reality is God’s creative love, which goes as far as willingness to suffer in sympathy with the other. Human existence in general reminds us that all of us are dependent on the generosity of others from the beginning and throughout life. Considering human beings only as individuals apart from their human relationships of interdependence makes no realistic sense and is a spiritually impoverished attitude.

There are also important facts here about the mother’s relationship with the father, a relationship that affects the child both directly and indirectly. The mother-father-child relationship, as mentioned in the beginning, is a concrete reflection of the Divine Trinity in which the Three Divine Persons give themselves to each other totally in a love that is creative and fruitful. The mother-father-child trio is a human image of the Trinitarian love in which the distinction of Persons is the source of the most perfect unity and love. The mother, father and their unborn child, as three distinct individuals, are in a relationship that does not lead to disunity but to the strongest bond of love that exists among humans, and the most intimate communication and mutual dependence. The non-materiality of this love points to the spiritual nature of the soul that directs the development of the life of the child, and of the maternal soul that responds to the otherness of the tiny human being she carries in her womb. The father’s experience of communication is more external, so that, despite the fact that the child carries his genes as much as the mother’s, his response is even more dependent on a spiritual/psychological decision.

There are implications in this reality for the most serious of moral/social issues of our day: in vitro fertilization, surrogate motherhood, sperm donation, embryonic stem cell research, abortion and single motherhood. Further study of each of these issues in light of what we know about embryology and healthy child-bearing should be encouraged. The very destiny of humanity is at stake in whether we take seriously the importance of “peace in the womb”.


1 Thomas Aquinas in his commentary on Boethius’s De Trinitatae.

2 Halle Morton, “Early pregnancy factor: An extracellular chaperonin 10 homologue”, Immunology and Cell Biology, (1998) 76, 483-496.

3 Ibid.

4 Ibid.

5 W.A. Castro-Rendon et al., “Blastocyst-endometrium interaction: intertwining a cytokine network”, Brazilian Journal of Medical and Biological Research (2006) 39: 1373-1385. See also K. Diedrich et al., “The role of the endometrium and embryo in human implantation”, Human Reproduction Update, Vol. 13, No. 4, 365-377, 2007; and R. Michael Roberts et al., “Maternal Recognition of Pregnancy”, Biology of Reproduction, Vol. 54, 294-302, 1996.

6 Pro-abortion leader Dawn Johnsen has claimed that pregnancy is “involuntary servitude” for the mother, which violates the 13th Amendment’s prohibition against slavery (legal brief for Webster v. Reproductive Health Services, 1989). Why, then, are most women overjoyed to find they are carrying a child in the womb? Such a negative attitude only occurs as a result of the rejection of a woman’s naturally maternal constitution as a life-giving, love-bearing human being whose fertility is a God-given gift. This denial is not reflective of the reality of procreative love intrinsic to human life.

7 Vijayakrishna K. Gadi and J. Lee Nelson, “Fetal Microchimerism in Women with Breast Cancer”, Clinical Research Division, Fred Hutchinson Cancer Research Center and Department of Medicine, University of Washington, Seattle, WA. See also online article: Michael Verneris, M.D., “Fetal microchimerism — what our children leave behind”, Blood, Journal of the American Society of Hematology, Nov. 15, 2003, Vol. 102, No. 10, 3465-3466:

8 Thomas Verny, MD, The Secret Life of the Unborn Child, (New York: Bantam-Doubleday-Dell Publishing Group, Inc., 1981), 47-48. See also “Frank Lake’s Maternal-Fetal Distress Syndrome: An Analysis”, by Stephen M. Maret, Ph.D. Professor of Psychology, Caldwell University.

9 Verny, Secret Life, 47-48

10 Ibid., 89.

11 Ibid., 88.

12 Ibid., 49-50.

13 Ibid., 161.

Kathleen Curran Sweeney has worked for several years in the pro-life arena. She holds a Master’s degree in Theological Studies in Marriage and Family from the John Paul II Institute in Washington, DC, an MA in history from the University of Washington, and a BA from Seattle University. She has published articles on pro-life topics, bioethics, education, and history in various publications, including Social Justice Review, Homiletic and Pastoral Review, Linacre Quarterly, and Logos. She and her husband live in Arlington, Virginia and have a grown son and daughter.

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