Placental Anatomy & Function: Basics From A Pro Placenta Encapsulation Trainer

The placenta is an incredibly unique organ, and it’s important to understand normal placental anatomy and physiology as well as deviations from the norm in order to make informed decisions about which placentas are suitable for consumption.

The placenta has a dark maroon, almost blueish color and measures, on average, 22cm in length. “Excessively long umbilical cords have intrinsically reduced vascular resistance and are more prone to hypercoiling, entanglement, and prolapse. Because the placenta is primarily a fetal organ, placental size normally correlates with fetal size and health. Placental weight is directly proportional to fetal weight, and at term, a typical fetal to placental ratio is {one to} seven,”[1] which means it averages a weight of about one pound.

No two placentas are the same; they are all as unique as a fingerprint. The placenta is the only organ that’s compatible with two separate sets of genes and blood types. It’s also the only disposable organ that the human body creates and then naturally sheds once its job is complete.

The placenta is formed from the same sperm and egg cells that form the baby, and its development begins when the blastocyst (a tiny form of cells that become the baby) implant on the uterine wall. The outer layer of the blastocyst becomes the amniotic sac which encases the developing baby. The baby is connected to the placenta via the umbilical cord. The cord is comprised of two arteries and one vein which are vital in the transfer of oxygen and nutrients from the placenta to the baby.  “The placenta is a vascular organ and any developmental interference with the basal plate blood supply or architectural disruption during pregnancy can yield life threatening bleeding, and jeopardize maternal and fetal well-being. The most critical interfaces include those between placenta and uterus, and the pipeline between placenta and fetus, the umbilical cord.”[2]

There are several cord abnormalities that can develop, one of the more common issues is a single artery cord which can cause IUGR (intrauterine growth restriction) and failure to thrive. When a placental or cord abnormality occurs, the medical care provider will often want to take the placenta to pathology for examination.  Please reference the section in this book on protecting the placenta from confiscation for helpful questions and decision frameworks for handling this issue.

The placenta has two sides, maternal and fetal. The maternal side (also known as the Duncan), imbeds into the side of the uterus during pregnancy via the cotyledons. The cotyledons are raised tissue masses on the maternal side of the placenta and in-between them are small gaps called sulci that are filled with the mother’s blood. Once the placenta is attached to the uterine wall, it has constant access to the mother’s blood supply and is able to transfer oxygen, hormones, and nutrients to the baby. The sulci and cotyledons distribute the blood into the middle section of the placenta which is rich with vascular architecture. 

The intricate vein structure of the placenta can be seen by observing the fetal side. I (Ashley here!) think it’s interesting to know that this is the first thing the baby sees when they open their eyes at around 27 week’s gestation. They spend most of their time looking at this ‘tree of life pattern’ for the rest of the pregnancy. This is also the side that the umbilical cord inserts into. The chorionic veins extend into the fetal side of the placenta.  Once they leave the fetal side, they extend into the middle portion (intervillous space), their function changes, and they are now called villi. The villi enable the baby to receive the nutrients and hormones from the mother’s blood without mixing her blood supply with the baby’s.  The villi have a coating on them called syncytiotrophoblast, which allows everything but the red blood cells to pass through the placenta.

Amniotic Membranes

Programs other than the Brilliant Birth Academy training usually advise placental encapsulators to discard the placental amniotic membranes.  This is an extremely unfortunate waste of highly valuable material![3] MiMedx® Group, Inc., for example, is a multi-million dollar corporation that uses a dehydrating technique (similar to how all placental encapsulators dehydrate placental tissue).  Their promotional material states that this process “protects the delicate scaffold of the amniotic membrane, leaving an intact extracellular matrix resulting in a durable graft.”[4] MiMedx® has “distributed over 700,000 amniotic tissue grafts worldwide and achieved profound clinical outcomes in multiple therapeutic areas including ophthalmology, spine, chronic wounds, dental, orthopedic surgery, sports medicine, and urology.”[5]

(Side Note: The company also raises awareness on how human tissue can promote bioactive healing and educate the wider medical community on the possibilities of regenerative medicine. This company closes out their corporate description by stating that they are “dedicated to the development and support of thoughtful and effective philanthropic programs to help those in underserved medical areas in need of healing.”[6] We wanted to highlight this both because they are an inspiration of how high levels of profitability and high levels of contribution can be achieved beautifully, and also because now that you have this book in hand, you too can emulate this example of spreading information on the possibilities of regenerative medicine, especially for our vulnerable special-needs children who need it so desperately. Armed with this informative tool, you too can become an advocate for the regenerative properties of the placenta both to families and health care professionals within your sphere of influence. Tag! You’re it!)

The company creates several product lines that regenerate damaged or diseased tissues by delivering human extracellular matrix components, essential growth factors, and specialized mediating cytokines.[7] The methods explained in this book will enable you to easily replicate a similar dehydration process that will preserve human amniotic membrane and placental tissue.  This results in a minimally manipulated tissue product that will heal precisely in the area of the body’s most critical need. In short, don’t throw the amniotic membranes away! And spread the word, because this tissue is impressive!  Let’s have a look at its anatomy, function, and regenerative capacities.

“Human amniotic membrane is comprised of the innermost layer of the placenta and lines the amniotic cavity. The membrane is composed of multiple layers including a single layer of epithelial cells, a basement membrane and an avascular connective tissue matrix.”[8] The tissues of the placenta have a complex interrelationship of materials that each have their own prominence of various stages of gestation.[9]  These placental tissues also have several different physiological characteristics that can vary in use during gestation and can also vary in therapeutic use after delivery.

Amniotic membrane is a unique material that has many types of collagen, a flexible but structural extracellular matrix (ECM), and importantly for us, it also contains essential, active, healing growth factors such as epidermal growth factor (EGF), transforming growth factor beta (TGF-b), fibroblast growth factor (FGF), and platelet derived growth factor (PDGF).”[10]

“Amniotic tissues have also shown little to no HLA-A, B, C antigens and β2 microglobulin.”[11] This is significant because these cell surface molecules are a main determinant in transplant outcomes. “These surface cell markers that make it possible for the immune system to determine what belongs and what doesn’t belong in an individual’s body. When the immune system encounters foreign markers, or antigens, on a cell, it generates antibodies and other substances to destroy what it perceives as an invader.”[12] HLA-B and HLA-C human leukocyte antigens (HLA) are a type of human MHC Class I cell surface receptors. “This surveillance system helps defend the body against things that can cause it harm. This protective mechanism, however, is also behind a recipient’s rejection of bone marrow, which carries surface markers that say, ‘foreign to the body’.”[13] When cytotoxic T-cells ‘patrol’ the body’s blood supply, they ‘read’ the human leukocyte antigens on the cell’s surface. Cytotoxic T-cells bind to foreign peptides and then kill the cells. This is one process the body uses to eliminate cells infected by a virus, cancerous cells expressing proteins they shouldn’t be, and foreign cells such as from a transplant.[14]

A mismatch in MHC Class I molecules is the primary cause of transplant rejection, which is why it’s so significant that amniotic tissues lack these human leukocyte antigens cell surface receptors. The body doesn’t read them as foreign or attempt to eliminate them. David Steenblock, in his classic Umbilical Cord Stem Cell Therapy: The Gift of Healing from Healthy Newborns writes this:Bone-marrow stem cells bear HLA antigens that require cross-matching in order to minimize the possibility of an adverse reaction or rejection. Umbilical-cord stem cells, on the other hand, appear to present less of a risk of rejection or adverse reaction. Many studies have shown that even when mismatched cord blood is given to patients, the … immune response to the mismatched blood actually helps patients with leukemia fight their disease. In more than 150 patient treatments involving human umbilical-cord stem cells tracked over an almost three year period by Steenblock Research Institute, no such reactions were ever noted.”[15]

Placental Function

The placenta is essential for a healthy pregnancy. It functions starting at the fifth or sixth week of gestation until it’s expelled after the birth of the baby. “During pregnancy, the placenta permits the passage of nutrients, metabolites and metabolic gases, and provides physical and immunological protection to the developing fetus.  In addition, it produces a variety of steroids and important metabolic hormones.”[16]

Amazingly, the placenta is the only organ compatible with two sets of blood types and genes. This is because of the above described inner-placental barrier structure. This allows for situations when a mother who is Rhesus negative (Rh-) has a spouse and baby who are Rhesus positive (Rh+).  It has been suggested that raw placental consumption just after delivery can suppress the immunological response of creating antibodies should mom and baby’s blood intermingle.

By the end of a 40-week pregnancy, blood flows into the placenta at an astounding rate of approximately 600-700mL/min. The amount can vary depending on the condition of the uterus, scar tissue, and placental growth/health. The blood flow volume decreases sharply when the pregnancy becomes post-term (40+ weeks) which is one of many reasons proactive maternal care involves sensitivity to when the estimated due date has come and gone.[17]

Maternal blood carries oxygen and nutrients to the baby through the umbilical cord. The baby’s waste products, including their ‘pre-respiration’ carbon dioxide is absorbed into the umbilical cord and passed through the placenta into the bloodstream for the mother’s body to dispose.  The placenta is not a waste organ, but a facilitator organ. It’s constantly renewing the circulating blood, allowing for a clean transfer.  The placenta is also a protective filter. It keeps out most bacteria but doesn’t have the ability to filter out viruses, drugs, or alcohol.  The chorionic membrane is impenetrable to some molecular-weight drugs and toxins. The placenta also passes on the mother’s antibodies to the baby in order to keep the baby healthy for several months after birth. If the mother has acquired a natural immunity to a virus or disease, the antibodies that her body has created will be transferred to the baby via the placenta. This is the traditionally understood concept of ‘herd immunity’ operating naturally.

The fetus also contributes to the mother in surprising and unique ways. Research is finding an association between a migration of fetal cells into the mother’s system and a reduced risk of cancer; these facts are consistent with research on how mother’s life-spans extend with each pregnancy. Scientists are currently exploring the “exciting possibility that persistence of fetal cells in maternal tissue play a role in immune surveillance for cancer cells.”[18] Simply put— each child a mother carries may produce cells that actively scan for conditions that threaten the mother.

At a biological and physiological level, the evidence proves what we intuitively know: the fetus is never a ‘parasite’ but a loving, contributing part of our human family regardless of the length of their time with us or gestational age. What a beautiful world we live in.

The active migration of fetal cells into the mother begins in the first trimester. Detection of fetal DNA in maternal blood is an innovation in non-invasive prenatal genetic and fetal sex diagnosis that is currently being implemented across the US, so doctors may be able to tell the sex of future pregnancies with a simple blood sample! A mother literally has cells from every child (post 10+ weeks) she has conceived (aborted, miscarried, or successfully delivered); they are literally a part of her. “As surprising as this intimate juxta positioning of maternal and fetal cells is in the uterus, equally unexpected is the fact that fetal cells traffic into the maternal blood, lodge within maternal organs and, in some women, persist for decades.”[19]

Immunology in pregnancy is a physiological miracle, and part of the reason why transplant outcomes with the placenta are so well received. For example, white blood cells in the pregnant uterus are in a sedated state of immune tolerance when they meet fetal cells which are technically ‘foreign cells’. “Human pregnancy is invariably marked by genetic differences between the fetus and mother, but safety of the fetus from immune rejection is provided by multiple, highly diverse systems operating mainly at the maternal–fetal interface. The mechanisms mentioned above and other more subtle processes carry out this mission effectively without compromising systemic immunity or the overall health of the mother…Considerable hard evidence supports the idea that fetal tissues program the maternal uterine cells for tolerance, either directly or indirectly.”[20]

“Fetal and maternal cells reside side by side without evidence of immune reaction” with mechanisms that may be continuously applied when the placental tissue is donated to a third party.[21] There are fascinating and well-documented mechanisms that cause this uteroplacental tolerance, and even some newer intriguing evidence that the white blood cells and other components of the immune system proactively support the pregnancy.[22] The mother’s defense systems protect the pregnancy, however this adaptive immune system is part of what predisposes the pregnant uterus to infections which is a major cause of fetal loss.

The placenta produces several valuable hormones during the 40-week gestation that literally sustain the pregnancy and provide benefits into the postpartum period. “Recently we have learned that the placenta plays a dynamic regulatory function by sensing the concentration of available nutrients and adapting placental metabolism to sustain fetal growth. There is evidence to suggest that the placenta can proactively regulate its metabolism to change the profile of nutrients presented to the fetus. The placenta is thus an active and pivotal partner with both the fetus and mother in determining fetal growth.”[23]

  • Estrogen: This hormone encourages the production of prolactin and causes the uterus to grow and stretch as the baby matures.
  • hCG (Human Chorionic Gonadotropin): This hormone serves early on as an indication to the mother (via a urine or blood test) that she’s pregnant. The level of hCG will rise and fall throughout the pregnancy. It will ensure that the placenta continues to produce estrogen and progesterone which are vital to the baby’s development.  Elevated hCG levels should not be present within a few weeks of delivery, but if it is, this could be an indication that there may be placental tissue remaining in the uterus.  If the mother is experiencing prolonged bleeding and clotting, an at-home pregnancy test can let her know if her hCG levels are too high (positive test result), and she can contact her care provider.  If her test result is negative, she may just be physically exerting too much.
  • HPL (Human Placental Lactogen): This hormone is released by the placenta, and it stimulates the production of prolactin, the hormone needed to produce breast milk. HPL also regulates both maternal and fetal glucose, protein, and fat levels. When you have a placenta that has released too much HPL, the result can be gestational diabetes.  Once the placenta is detached and delivered, HPL levels drop, and the mother is able to re-stabilize her blood glucose levels.
  • IgG (Immunoglobulin G) antibodies: These help to protect the baby in the womb against infections, toxins, and promotes healing and recovery from illness.
  • Oxytocin: This brings about hormonal and chemical changes in the body, causes contractions for birth, promotes lactation, and encourages bonding.
  • Placental Opioid Factor: Pain-reducing opioids released during labor and delivery are in the amniotic fluid and in the placenta.
  • Progesterone:  This hormone maintains the pregnancy by keeping the mother’s uterus from shedding its lining which would result in loss of the baby. Progesterone is vital for full-term development. The corpus luteum produces progesterone until 8 week’s gestation, when the luteal-placental shift takes place, and the placenta takes over production.

[1] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.

[2] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.

[3] Baradaran-Rafii A; Aghayan H; Arjmand B; and Javadi M. “Amniotic Membrane Transplantation.” Iranian Journal of Ophthalmic Research (2)1. 2007. pp 58-75.

[4] <> Accessed 1 August 2017

[5] <> Accessed 1 August 2017

[6] <> Accessed 1 August 2017

[7] See this amazing article for a glimpse into what has been done in this field and what is possible in the future: John, T. “Human Amniotic Membrane Transplantation: Past, Present, And Future.” Ophthalmology Clinics of North America Journal. (16). 2003. pp 43-65.

[8] Niknejad H; Peirovi H; Jorjani M; Ahmadiani A; Ghanavi J; Seifalian AM “Properties of the Amniotic Membrane for Potential Use in Tissue Engineering.” European Cells & Materials Journal. (15), 2008, pp 88-99.

[9] Rahman I; Said DG; Maharajan VS; Dua HS “Amniotic Membrane In Ophthalmology: Indications and Limitations.” Eye. (23)10, 2009. pp 1954–1961.

[10] Kay H; Nelson D; Wang Y. The Placenta: From Development to Disease. Wiley-Blackwell. 2011.

[11] Baradaran-Rafii A; Aghayan H; Arjmand B; and Javadi M. “Amniotic Membrane Transplantation.” Iranian Journal of Ophthalmic Research (2)1. 2007. pp 58-75.

[12] Steenblock, David A. Anthony G. Payne. Umbilical Cord Stem Cell Therapy: The Gift of Healing from Healthy Newborns. Basic Health Publications, Inc. Laguna Beach, 2006.

[13] Steenblock, David A. Anthony G. Payne. Umbilical Cord Stem Cell Therapy: The Gift of Healing from Healthy Newborns. Basic Health Publications, Inc. Laguna Beach, 2006.

[14] Daniel M. Davis. The Compatibility Gene. How Our Bodies Fight Disease, Attract Others, and Define Ourselves. Oxford: Oxford University Press. 2014

[15] Steenblock, David A. Anthony G. Payne. Umbilical Cord Stem Cell Therapy: The Gift of Healing from Healthy Newborns. Basic Health Publications, Inc. Laguna Beach, 2006.

[16] Kay H; Nelson D; Wang Y. The Placenta: From Development to Disease. Wiley-Blackwell. 2011.

[17] Grannum PA, Berkowitz RL, and Hobbins JC The Ultrasonic Changes in the Maturing Placenta and Their Relation to Fetal Pulmonic Maturity. American Journal of Obstetrics and Gynecology 133(8):1979, pp 915–22.

[18] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.

[19] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.

[20] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.

[21] Hunt JS and Petroff MG (“Molecular Immunology of the Maternal–Fetal Interface. In: Aplin JD, Fazleabas AT, Glasser SR, and Giudice LC (eds) The Endometrium. 2nd edn. New York, NY: Informa Healthcare; pp. 524–45.

[22] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.

[23] Helen Kay, D. Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. Wiley-Blackwell, 2011.


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