Afterbirth is the collective term for everything that comes out of the uterus after the baby is born: the placenta, the fetal membranes (sometimes called the “bag of waters”), and the umbilical cord. Together, these tissues weigh roughly a sixth of the baby’s weight and represent a temporary organ system that kept the fetus alive for nine months. In most deliveries, the afterbirth is expelled within about six minutes of the baby’s arrival, though it can take longer, and its delivery is considered the third and final stage of labor.
The Placenta, Membranes, and Cord
The largest and most prominent part of the afterbirth is the placenta, a disc-shaped organ that at full term typically measures about 20 centimeters across and 2 to 3 centimeters thick. One side, the maternal surface, is dark red and divided into lobes called cotyledons. The other side, facing the baby, is smooth and shiny, covered by the amnion membrane, with the umbilical cord usually inserting near the center.
Surrounding the placenta and lining the inside of the uterus during pregnancy are the fetal membranes. These consist of two thin layers: the inner amnion, which directly contains the amniotic fluid the baby floats in, and the outer chorion, which sits against the uterine wall. When people talk about a woman’s “water breaking,” they mean the rupture of these membranes. After delivery, the membranes peel away from the uterine wall and come out attached to the edge of the placenta, looking like a translucent sac.
The umbilical cord connects the baby’s belly to the center of the placenta. It contains two arteries and one vein, all embedded in a slippery, gel-like substance called Wharton’s jelly, which cushions the blood vessels against compression and kinking.1PubMed Central. The Pathophysiology of Wharton’s Jelly and Its Impact on Fetal and Neonatal Outcomes: A Comprehensive Literature Review Despite what you might assume, the arteries carry deoxygenated blood away from the baby to the placenta, and the single vein carries oxygen-rich blood back. This reversal of the usual artery-vein roles is one of the quirks of fetal circulation.
What the Placenta Actually Does
The placenta is far more than a passive filter. It functions as the baby’s lungs, kidneys, liver, and immune barrier all in one. Oxygen and nutrients pass from the mother’s blood through the placental tissue into the fetal bloodstream, while carbon dioxide and waste products travel the other direction.2Thrombosis Research. Growth and function of the normal human placenta This exchange happens across a thin barrier of cells called the trophoblast, which lines millions of tiny finger-like projections called villi that dangle in pools of the mother’s blood. The surface of these villi is covered with microvilli, microscopic brush-like extensions that massively increase the area available for exchange.3American Journal of Obstetrics and Gynecology. Surface structure of the human term placenta and of the uterine wall post partum in the screen scan electron microscope
Nutrient transfer is not passive diffusion for most substances. The placenta uses dedicated transport proteins for sugars, amino acids, and other building blocks, actively moving them into the fetal circulation based on demand.4PubMed Central. Maternal-fetal nutrient transport in pregnancy pathologies: the role of the placenta The fetus also has a special form of hemoglobin that grabs oxygen more tightly than the mother’s hemoglobin, which helps pull oxygen across the placental barrier even though the oxygen levels there are relatively low.5PubMed. Evolution of placental function in mammals: the molecular basis of gas and nutrient transfer, hormone secretion, and immune responses
The placenta is also a hormone factory. The outer layer of the villi, the syncytiotrophoblast, churns out hormones that maintain the pregnancy and reshape the mother’s metabolism to support fetal growth.6PubMed. Human placenta as an endocrine organ These include human chorionic gonadotropin (the hormone detected by pregnancy tests), human placental lactogen (which alters the mother’s blood sugar and fat metabolism to ensure the fetus has fuel), and placental growth hormone.7PubMed Central. Secretion of placental peptide hormones: functions and trafficking In a real sense, the placenta acts as the baby’s endocrine system until the baby’s own glands are mature enough to take over.
How the Afterbirth Is Delivered
Once the baby is out, the uterus continues to contract. The uterine wall shrinks dramatically, but the placenta does not. This mismatch in surface area causes the placenta to buckle and shear away from the uterine wall at a natural separation zone called the Nitabuch membrane, a thin layer of tissue at the junction between maternal and placental cells.8PubMed. Failure of placental detachment in accreta placentation is associated with excessive fibrinoid deposition at the utero-placental interface After detachment, a few more contractions push the placenta and membranes down through the birth canal.
In most cases, this takes about five to six minutes. A large study of singleton term deliveries found a median third-stage duration of six minutes, with complications rising after the 30-minute mark.9American Journal of Obstetrics and Gynecology. Third stage of labor: evidence-based practice for prevention of adverse maternal and neonatal outcomes – Section: Physiology of the third stage of labor Other research has produced similar figures, with a mean around six minutes and a standard deviation of about five, meaning most placentas arrive quickly but a minority take longer.10PubMed Central. The duration of the third stage of labor and related factors
After delivery of the afterbirth, the uterus continues to clamp down. The muscle fibers of the uterus act as “living ligatures,” squeezing the blood vessels that used to feed the placental site. This rapid contraction is what prevents massive bleeding. If the uterus fails to contract properly, a condition called atony, it is the leading cause of postpartum hemorrhage.11PubMed. Abnormal Uterine Involution May Lead to Atony and Postpartum Hemorrhage: A Hypothesis, With Review of the Evidence
Active Versus Hands-Off Management
Clinicians have two broad approaches to managing the afterbirth delivery. Active management typically involves giving the mother an injection of a uterine-contracting drug (like oxytocin) right after the baby is born, controlled traction on the cord, and sometimes uterine massage. Expectant management, by contrast, lets the placenta deliver on its own with gravity and the mother’s pushing effort, intervening only if needed.
A Cochrane review comparing the two approaches found that active management may reduce the risk of heavy bleeding (over 1,000 milliliters of blood loss) and lower the likelihood of postpartum anemia.12PubMed Central. Active versus expectant management for women in the third stage of labour However, active management also came with trade-offs: more side effects such as nausea, higher blood pressure, and increased afterpains, along with more women returning to the hospital with later bleeding. Babies in the active management group also tended to have slightly lower birth weights, likely because early cord clamping reduced the blood transferred from the placenta.13Cochrane Database of Systematic Reviews. Active versus expectant management of the third stage of labour For most hospital births today, some form of active management is standard practice, though the specifics vary.
When the Afterbirth Does Not Come Out Cleanly
A retained placenta, where part or all of the afterbirth stays stuck in the uterus, is one of the most serious complications of the third stage. If the placenta does not separate within 30 minutes, the risk of heavy bleeding climbs, and manual removal under anesthesia is often necessary.
The most concerning form of this problem is placenta accreta spectrum, where the placenta grows too deeply into the uterine wall. Normally, the placenta sits on a layer of uterine lining called the decidua, and the Nitabuch membrane provides a clean separation plane. In accreta, that separation zone is defective. Current research points to scarring from previous cesarean deliveries as the primary risk factor: large scar defects in the lower uterus disrupt normal lining formation and allow placental tissue to invade far deeper than it should.14PubMed. New insights into the etiopathology of placenta accreta spectrum In more than 70% of accreta samples, thick deposits of a fibrin-like material were found between the placental villi and the uterine wall, distorting the normal detachment plane.8PubMed. Failure of placental detachment in accreta placentation is associated with excessive fibrinoid deposition at the utero-placental interface Accreta spectrum ranges from mild (accreta, where villi attach to the muscle surface) to severe (percreta, where they grow through the uterine wall entirely), and management can require hysterectomy in serious cases.15Clinical Obstetrics and Gynecology. Pathophysiology of Placenta Accreta Spectrum Disorders: A Review of Current Findings
What Happens to the Afterbirth Next
In most hospital settings, the delivered afterbirth is examined briefly by the attending clinician, who checks that the placenta and membranes appear complete (missing pieces could mean tissue is retained in the uterus). Routine pathological examination of every placenta is not standard. Research has suggested that lab examination is valuable in high-risk cases or when there have been complications, but sending every placenta for analysis is not considered cost-effective for routine low-risk deliveries.16PubMed Central. Pathologic examination of the placenta and its benefits in treatment plan or follow-up of patients: a cross-sectional study That said, when a placenta is examined under a microscope, it can reveal information about infections, blood-flow problems, and developmental issues that might affect the baby’s health going forward.17Obstetrics & Gynecology. Pathologic Examination of the Placenta and Observed Practice
After examination, placentas in most hospitals are treated as medical waste and incinerated. Some families request to take the afterbirth home, and hospital policies on this vary. A survey of perinatal pathologists found that about 60% of respondents allowed placenta release, with burial being the most commonly cited reason, followed by consumption or encapsulation.
Delayed Cord Clamping and Cord Blood
One of the biggest shifts in afterbirth-related care over the past two decades has been the move toward delayed cord clamping. Instead of cutting the umbilical cord within seconds of birth, many guidelines now recommend waiting at least 30 to 60 seconds, or even longer, to allow blood from the placenta to transfer to the baby.
A randomized trial found that babies who had their cords clamped later had about 45% higher iron stores at four months of age compared with early-clamped babies, and far fewer cases of iron deficiency, with no increase in complications like jaundice requiring treatment.18BMJ. Effect of delayed versus early umbilical cord clamping on neonatal outcomes and iron status at 4 months: a randomised controlled trial Other studies have confirmed that delayed clamping raises newborn hematocrit and hemoglobin levels, and the concerns about jaundice that long made clinicians hesitant have largely been put to rest.19PubMed Central. The Impact of Umbilical Cord Clamping Time on the Infant Anemia: A Randomized Controlled Trial For preterm infants, the benefits extend further, with evidence suggesting reduced rates of bleeding in the brain and more stable circulation in the critical early hours.20Medicine & Health. Delayed Cord Clamping at Delivery of a Newborn- A Position Statement by the College of Paediatrics and the College of Obstetricians and Gynaecologists, Academy of Medicine of Malaysia
The blood remaining in the placenta and cord after clamping, known as cord blood, is itself a resource. It is rich in stem cells, including hematopoietic stem and progenitor cells that can rebuild a patient’s blood and immune system.21PubMed Central. Umbilical cord blood: a comprehensive review of protective and restorative properties in clinical applications – a narrative review Cord blood banking, either through public donation or private storage, has been available since the late 1980s. Public cord blood banks make units available for transplant to anyone who needs them, and thousands of transplants using cord blood have been performed for leukemia, immune disorders, and inherited metabolic diseases. Cord-blood-derived stem cells also show promise in regenerative medicine research, with early-stage investigations into conditions as varied as autoimmune disease and cerebral palsy.22PubMed Central. Bone marrow and umbilical cord blood human mesenchymal stem cells: state of the art
Medical Uses of Placental Tissue
Beyond cord blood, other parts of the afterbirth have found their way into medicine. The amniotic membrane, the innermost layer of the fetal membranes, has been used therapeutically for over a century. It has anti-inflammatory and anti-scarring properties that make it useful in wound care and eye surgery, where it is applied as a biological bandage to promote healing. Modern applications include corneal reconstruction, treatment of chronic non-healing wounds, and repair of the conjunctiva after surgery.23PubMed Central. Amniotic Membrane Transplantation for Wound Healing, Tissue Regeneration and Immune Modulation These grafts come from donated placentas collected after planned cesarean deliveries, screened for infectious diseases, and processed under sterile conditions. You will not find these products at a health food store; they are regulated medical devices or tissue products used in clinical settings.
Cultural Practices Around the Placenta
Many cultures have deep traditions involving the afterbirth. Across indigenous communities worldwide, the placenta is treated as spiritually significant rather than medical waste. Common practices include burial, sometimes under a tree planted to grow alongside the child, as well as rituals intended to protect the newborn’s future health and fortune.24PubMed Central. The Disposal of Placenta among Indigenous Groups Globally: An Integrative Literature Review In Māori tradition, the word for placenta, “whenua,” is the same word for land, reflecting the belief that burying the placenta connects a person to their ancestral home.
Interestingly, while nearly all nonhuman mammals eat the placenta after birth, human placentophagy is historically rare. A cross-cultural survey of 179 societies found a conspicuous absence of traditional placenta consumption across human cultures, making humans an outlier among mammals.25PubMed. In search of human placentophagy: a cross-cultural survey of human placenta consumption, disposal practices, and cultural beliefs The modern trend of placenta encapsulation, where the organ is dehydrated, ground into powder, and packed into capsules, emerged primarily in North America starting in the 1970s and has gained popularity through social media. Proponents claim it boosts energy, improves mood, and increases breast milk supply.
The evidence for these claims is thin. Self-reported benefits exist, but controlled research has not substantiated them. A review of available evidence noted that the purported benefits lack scientific rigor, and the preparation method (raw, cooked, dehydrated, or encapsulated) alters the placenta’s components unpredictably.26PubMed Central. Consumption of Maternal Placenta in Humans and Nonhuman Mammals: Beneficial and Adverse Effects Possible risks include infections (bacterial contamination during processing), exposure to environmental toxins that may have accumulated in placental tissue, and hormone levels that could affect the mother or a breastfed infant.27Journal of Obstetric, Gynecologic & Neonatal Nursing. Consumption of the Placenta in the Postpartum Period The CDC has flagged at least one case where a newborn developed a serious bacterial infection linked to contaminated placenta capsules taken by the mother.
Is the Placenta Sterile?
For decades, the prevailing assumption was that a healthy placenta is sterile, with the baby living in a germ-free environment until birth. Around 2014, a widely covered study proposed the existence of a “placental microbiome,” suggesting that bacteria normally colonize the organ. This sparked intense debate and a wave of follow-up research.
The weight of evidence has since swung firmly back toward sterility. Multiple rigorous studies using careful contamination controls found no consistent microbial population in placentas delivered at term from uncomplicated pregnancies.28PubMed Central. Does the human placenta delivered at term have a microbiota? Results of cultivation, quantitative real-time PCR, 16S rRNA gene sequencing, and metagenomics When bacteria were detected, they could not be distinguished from contamination introduced during sample collection or lab processing. A study of 76 term pregnancies using both DNA sequencing and bacterial culture experiments came to the same conclusion: no evidence for a placental microbiome.29PubMed. No evidence for a placental microbiome in human pregnancies at term The earlier positive findings appear to have been artifacts of working with samples that contain very little microbial material, where even trace contamination from reagents or skin can look like a resident bacterial community. This episode is a useful reminder that dramatic claims in biology sometimes do not survive replication.
None of this means the placenta is always free of bacteria. Infections can and do reach the placenta, a condition called chorioamnionitis. The point is that bacteria are not supposed to be there as a normal feature of healthy pregnancy, and their presence generally signals a problem rather than a symbiotic relationship.