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Mothering › Pregnancy Articles › The Amazing Placenta

The Amazing Placenta

By Sarah J. Buckley, MD
Issue 131, July/August 2005


Durga illustration - placentaJacob's conception was unexpected, and unknown to us for several weeks. We'd been on holiday in Tasmania, Australia's small "south island," and on the ferry trip home had carried not only Emma (four years) and Zoe (one year), but also their brother-to-be—a tiny mass of cells barely a week from conception. As I slept fitfully on my bunk, Jacob's blastocyst, looking like a tiny blackberry just 2 millimeters in diameter, had already rolled down one of my fallopian tubes and was busy burrowing into the dark, thick lining of my womb.


For the next two weeks, Jacob-to-be obtained his nourishment directly from this rich lining, and I was oblivious to his presence. Quiet he may have been, but he was not quiescent—it was during this important time that Jacob's cells first became specialized, and he began to form his placenta. Deep inside his blackberry-shaped blastocyst, some of his cells clumped together to form an "inner cell mass" that would later become Jacob's body, umbilical cord, and amniotic sac. Other cells migrated outward to form the surrounding trophoblast, which would become Jacob's placenta.


Once created, his trophoblast began infiltrating my womb more deeply, releasing enzymes to dissolve my uterine cells and blood vessels. In this way, Jacob created lakes of my blood—the placental lacunae—for his sustenance. Even as I attributed my overdue period to intensely breastfeeding Zoe while on holiday, Jacob's villi—fingerlike projections from his developing placenta, each containing a newly formed blood vessel—were growing and dipping into my lacunae, our bloodstreams separated by the thinnest, most permeable of membranes. (1)


Through this membrane, for the rest of the pregnancy, I would pass on all the nutrients and growth factors that Jacob's body needed, and he would pass his wastes back to me. Furthermore, this membrane would prevent our blood cells from mixing, and my immune system from rejecting Jacob as a foreign invader.


As well as this, Jacob's villi were anchoring his developing placenta, acting as his roots in the firm soil of my womb-garden, and his body stalk—the tissue that would later become his umbilical cord—was keeping his embryonic body alive and attached to his placenta, like a floating astronaut's lifeline. At this time his body was smaller than a kidney bean, and just beginning to form limb buds—his future arms and legs.


Jacob's developing placenta had another important early task, the production of placental hormones, and it was this that revealed his presence. Under the influence of human chorionic gonadotropin (HCG), which his placenta had been producing in increasing amounts since a few days post-implantation, I was beginning to feel decidedly queasy. I finally realized that I was pregnant when this nausea visited me in the middle of the night. HCG was also the hormone that turned my pregnancy test predictably positive the next day.


Over the next few weeks I had intense, all-day morning sickness. Maybe it would have been more tolerable had I realized that this shift, which put me off spicy and bitter foods as well as tea and coffee, was actually caused by Jacob's placental hormones working to protect him from the high levels of natural toxins that such foods contain. Furthermore, my heightened sense of smell—another trigger for nausea—was ensuring that I ate only the freshest foods and avoided pungent aromas and cooking vapors, which could also contain inhalable toxins. My nausea began to subside as Jacob grew beyond the embryonic stage (about eight weeks after conception) and was almost gone by the fourth month of pregnancy, when his organ systems were essentially fully formed and therefore less vulnerable to toxic damage. (2)


This two-month milestone (equivalent to 10 weeks from menstruation) marked the beginning of Jacob's life as a fetus. By this time, his body had reached 4 to 5 centimeters in length, and thanks to the nourishment delivered by his placenta, his weight had increased to a creditable 4 grams, or one-seventh of an ounce—220,000 times greater than his weight at conception. The trophoblast that had originally surrounded him had by now formed a near-mature placenta on one side and, on the other, a protective bubble, the chorion, that would eventually form part of Jacob's double-layered membranes.


Over the next two months, Jacob's placenta grew and spread. By mid-pregnancy, his placenta covered about half the wall of my uterus and was heavier than his body. Later in the pregnancy, Jacob's body would grow much more, so that at birth his placenta would weigh about one-sixth as much as his body. Jacob's versatile placenta was also able to migrate during pregnancy, moving slowly toward the best blood supply and away from areas of diminished supply. This mechanism, known as trophotropism, is thought to explain many irregularities in placental shape and structure, as well as the healthy upward movement of most placentas that are low-lying (placenta previa) in early pregnancy. (3)


Although external to his body, Jacob's placenta was his most essential organ, performing all the functions that his immature gut, lungs, immune system, kidneys, liver, and skin were not capable of in my womb.



Working in place of his gut, Jacob's placenta enabled him to extract all the nourishment that he needed from my blood in exactly the right amounts—and his placental hormones could ensure that what he needed was available. For example, if there was an insufficient blood supply for his needs, he could, through producing the right hormones, order my body to increase my blood pressure and so increase the amount of my blood that was delivered to his placenta. Similarly, if he needed more glucose, he could ask for it—and, as a side effect of raising my blood glucose levels, could possibly land me with a diagnosis of gestational diabetes. (4) Jacob's placenta—like every baby's—was a tireless advocate for his own health and survival.


With his lungs full of amniotic fluid and with no access to air, Jacob obviously could not breathe in my womb, but he was able to obtain all the oxygen he needed from my oxygenated blood, delivered via his placenta. Along with my oxygen, Jacob also ingested any toxins that I inhaled into my bloodstream, most of which were transferred through his placenta as efficiently as the nutrients from my blood. My early nausea had again protected him by making me averse to polluted air and by giving me a craving for cool, fresh air. Later in the pregnancy, when we decided to pull up the carpets in our bedroom—our version of preparing the nest—we kept Jacob's air fresh by choosing a floor varnish that would not emit toxic fumes.


Jacob's close attachment to me—the closest possible in human existence—presented some problems that his placenta could at least partly solve. If any bacteria had invaded my pregnant body and gained access to my bloodstream, his placenta could have filtered them out, to some extent. Smaller particles, however—including toxoplasmosis and viruses such as rubella and herpes, all potentially harmful to Jacob because of his immature immune system—would be more likely to slip through his placental filter. Luckily, Jacob's placenta also allowed some of my antibodies to pass through, giving him ready-made immunity to almost all the diseases I had encountered over my lifetime.


Jacob's placenta was unable to filter out drugs or other chemicals, so anything that was administered to me was also administered to him. Fortunately for both of us, neither my pregnancy nor my labor was complicated, and we avoided prescription drugs and painkillers of any kind. However, it is very likely that some of the chemicals in my diet—which was substantially but not entirely organic—as well as other toxins that I might have accumulated before my pregnancy, such as heavy metals (for example, lead and mercury), would have found their way into Jacob's body. (5) During his last few weeks in utero, his placenta transferred a rich and healthy store of iron—an essential metal—that would last him well into infancy.


Jacob's placenta was also an important site for detoxifying and expelling his bodily wastes, which could flow easily back into my bloodstream and be excreted through my body. This process kept a light load on his kidneys and liver—both immature organs in utero—while keeping mine busy. Not only was I eating and breathing for him, I was peeing for him as well.


Like all unborn babies, Jacob had practical difficulties with cooling off, enveloped as he was in my warm body. His placenta was therefore doing what his skin could not: offloading his excess heat into my cooler circulation. Luckily, Jacob's was a winter pregnancy, and this extra heat, which I positively radiated, kept me warm at night.


But, of course, neither Jacob nor I needed to spare a thought for these feats, performed continuously by his wondrous placenta as naturally and as necessarily as the beating of his heart. Jacob's placenta was his constant companion, a warm pillow humming gently with the flow of blood. (6) For me, his placenta was an idea rather than a tangible reality, but it was an integral part of how I imagined him in my belly, and of the pictures I drew during my pregnancy.


As Jacob's due date approached, we made some special preparations for his placenta. We planned a Lotus birth for Jacob, as we had for his sister Zoe, which involved not cutting the cord at all: Zoe had remained attached to her placenta until her cord came away from her navel on the sixth day. This had been a beautiful ritual, allowing Zoe a gentle transition between womb and world, and keeping us also in a serene, timeless space. Lotus birth had been fairly simple for us I had sewn a red velvet bag for her cord and placenta, which we bundled up with her for those few days.


Jacob's due date came and went, with several revisions and a lot of waiting. I enjoyed my three supposedly overdue weeks, and my instinct was always that my baby was thriving. My doctor offered me tests of placental function—essentially checks of the levels of hormones such as human placental lactogen (HPL) and estriol, which are produced or processed by the placenta—and we discussed scans and heart monitoring to check my baby more directly.


The conventional thinking has been that the placenta "ages" past term, potentially compromising the baby's growth, well-being, and ability to cope with labor. However, placental anatomists have shown that the placenta continues to expand and increase in surface area beyond 40 weeks, and that the placenta has a large "functional reserve." (7)



So Jacob's stalwart placenta was still growing and supporting him. Although the way that Jacob signaled his readiness for birth is still not known for certain, that message was no doubt relayed through his placenta. One likely messenger is corticotropin-releasing hormone (CRH), ordinarily a stress hormone secreted by the brain but produced in pregnancy by the baby's placenta. Placental CRH production rises steeply in late pregnancy, when it acts to prepare the baby's lungs for breathing and the mother's womb for labor.


I was expecting a nighttime labor—I'd had a few "false starts" during the previous nights—and sure enough, labor began around 1 a.m. It proceeded slowly and gently, giving Jacob ample recovery time between my contractions, each of which squeezed his placenta and so temporarily cut off his blood supply. Fortunately, Jacob, like all mammalian young, was superbly adapted to these periods of low oxygen supply, or hypoxia, in labor and birth, as evidenced by the quick recovery of his heart rate after each contraction. My midwife checked his heartbeat regularly; had I been in a hospital, an electronic fetal monitor (EFM) could have shown the same information?


After 11 hours or so, Jacob was born into the water in a tub in our back room, witnessed by his amazed sisters. Around 30 minutes later, I stood up to deliver his placenta into a plastic bowl. Jacob's unclamped cord and attached placenta created a few minor difficulties—my doctor had a rather difficult time collecting a sample of the cord blood (to check Jacob's blood group), and we had the challenge of keeping his placenta bowl afloat when Emma and Zoe climbed into the tub.


Because we didn't clamp or cut his cord, Jacob received his placentas final gift to him—a transfusion of an extra 100 milliliters or so of his own blood. This blood had been stored in his placenta and was designed to assist him at birth by filling the blood vessels in his lungs, kidneys, liver, gut, and skin—all the organs he hadn't used in utero—with oxygen-rich blood. Jacob's placental transfusion was also a safety net, able to tide him over if his breathing had not been established straight away.


If we had clamped Jacob's cord immediately after birth, he would also have missed out on the extra iron—about a month's supply—contained in his placental transfusion, as well as his own rich store of stem cells? Some experts in this area would add that we may have given Jacob protection from cerebralpalsy, attention deficits, and perhaps even autism, because we allowed his brain to receive the full blood supply intended for him by Mother Nature. (10-13) (Most of this extra blood is transferred in the first few minutes, but a longer delay in cord clamping—until the cord stops pulsing, or longer—allows the baby to regulate his or her own blood volume.)


All other mammals, and attendants in most traditional cultures, cut or bite through the baby's cord only after the placenta has been delivered—and with good reason. Jacob's placental transfusion reduced the size of his placenta by 100 ml, and my uterus was able to contract more efficiently around it, thus decreasing my chances of hemorrhaging. Jacob's less bulky placenta was also easy—and pleasurable—to birth.


After we left the water, we took a closer look at Jacob's placenta, which was still attached to him. It was a beautiful, round, full placenta: dark red on one side—the villous side, which had been attached to the wall of my womb—and glistening silver on Jacob's side, due to the covering of his membranes. Stretching out these membranes, we could almost re-form the watertight sac that had enveloped and protected Jacob for nine months; it might even have been possible to guess from its shape where his placenta had been attached to my womb. We marveled at Jacob's triple-vesseled cord, 60 cm or so long from his belly to his placenta, and branching out under the placental membranes like the trunk of his "tree of life," as the placenta has been called.


Had we measured Jacob's placenta, it would have been 20 to 25 cm in diameter (a little smaller than a dinner plate), 2 to 3 cm thick, and about 500 grams in mass. We did check it to ensure that it was complete before we patted it dry and placed it gently in a sieve to drain for a few hours. If placental fragments had remained in my womb, I could have risked hemorrhage or infection in the hours or days following birth.


For the next three days we dried and salted Jacob's placenta every 12 hours or so, then wrapped it carefully in a cloth diaper, and then in the red velvet bag I had sewn. Jacob's "breaking forth" time—the time between his birth and the separation of his cord—was quiet and still as we honored his original wholeness, and we respected his integrity through not choosing circumcision. We watched as his cord dried out and hardened from his umbilical end; it separated without any fuss on the fourth morning. (14) We kept Jacob's placenta in our freezer, even through a move between states. When Jacob was four, he chose a jacaranda tree to plant over it.


Lotus birth is a new practice that has not been officially recorded except among chimpanzees. According to Lotus-birth pioneer Clair Lotus Day, a chimp mother carries her baby's placenta until separation. However, almost all traditional cultures have beliefs and rituals that highlight our relationship to this extraordinary organ. In Bali, for example, the placenta, or ari-ari, is said to live on in spirit as the child's guardian angel; a Balinese child greets his or her placenta on rising in the morning and prays to it for protection at night. Every new moon and full moon, and on each holy day, offerings are placed at the burial site of the placenta. After death, the placenta is believed to accompany the deceased to heaven to testify as to whether the person fulfilled his or her duty in this lifetime. (15)



The place of placental burial is important in many cultures. Among some peoples, the placenta must remain hidden from evil spirits to safeguard the newborn baby; other burial practices emphasize the lifelong connection between placenta and child. For example, villagers in Zimbabwe believe that burying the placenta in the family home will ensure that their offspring will always return home. (16) Sir James Frazer, writing in the early 20th century, noted that "even in Europe many people still believe that a person's destiny is more or less bound up with that of his navel-string or afterbirth." Frazer reports that German midwives would give the dried navel-string to the father, telling him to preserve it carefully in order to keep the child healthy and free from illness. (17) Modern-day Lotus-birth advocate Jeannine Parvati Baker believes that we all have a strong connection to the place where our "navel string" and placenta are buried. (18)


The relationship with the placenta does not end with its disposal, whether by ritual burial or by hospital incineration. Placental symbolism is everywhere in our culture, from the handbags that we carry—holding our money, datebooks, and other items of survival—to the soft toys that we cram into our babies' cribs. Some believe that much of our culture's discontent and our urge to accumulate possessions—including all of the aforementioned—come from the traumatic loss of our first possession: our placenta. And each year we honor our placenta by lighting candles on our birthday cake—in Latin, the word placenta means "flat cake." (19)


Jacob's placenta has been his conduit, passing life from my body to his. Now this placenta—his womb-twin, his primal anchor—has gone back to the earth. Seven years after his birth, Jacob tells me "your placenta is like your heart;' and I realize that he received more than physical nourishment through his placenta. (20) Along with the oxygen, nutrients, hormones, and all the other placental gifts, Jacob also received my love, which was equally his sustenance in my womb, transmitted subtly but vitally by this amazing organ—the placenta.


Sarah J. Buckley is a family physician, a writer, and a full-time mother to Emma (14), Zoe (11), Jacob (9), and Maia Rose (4). Her book Gentle Birth, Gentle Mothering will be published in Fall 2005. See www. sarahjbuckley.com for details.

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