The placenta is an essential organ that develops during pregnancy to provide oxygen and nutrients to the growing baby. But what happens to the placenta after the baby is born? Here’s a look at how long the placenta stays alive and functional after delivery.
What is the Placenta?
The placenta is a temporary organ that begins developing early in pregnancy to sustain the growing fetus. It attaches to the wall of the uterus and connects to the baby via the umbilical cord. The placenta has several important roles:
- Transporting oxygen and nutrients from the mother’s blood supply to the fetal blood supply
- Removing waste products from the fetal blood supply
- Producing hormones to support pregnancy
- Providing a barrier against certain substances
The placenta receives blood supply from the uterine arteries and returns blood to the uterine vein. Fetal blood enters the placenta through two umbilical arteries and exits through the umbilical vein.
When Does the Placenta Form?
Development of the placenta begins shortly after the fertilized egg implants in the uterine lining, around day 6-12 after conception. The outer layer of the blastocyst begins transforming into the chorion, which will become part of the fetal side of the placenta. The inner cell mass becomes the bilaminar disc and then the trilaminar embryo.
In the second week after conception, the chorion develops finger-like projections known as villi. These villi invade and destroy the endometrial cells of the uterine wall and establish blood flow. This process allows nutrients and oxygen to diffuse from maternal blood into the fetal bloodstream.
Development continues throughout the first trimester. By weeks 10-12, the placenta is fully formed and begins secreting hormones like hCG and estrogen to support fetal growth.
When Does the Placenta Deliver?
The placenta is usually delivered within 30 minutes of childbirth, either before or after the baby. This is known as the third stage of labor.
There are two methods for delivery of the placenta:
- Physiological management: Allowing the placenta to deliver naturally through maternal effort and gravity. The uterus continues to contract after birth, shearing the placenta from the uterine wall. The placenta then descends into the vagina and is gently guided out by care providers.
- Active management: Administering oxytocin via IV after delivery to accelerate placental separation and contraction of the uterus. The umbilical cord is also clamped promptly and gentle traction applied to guide the placenta out.
Active management is more common in developed countries as it reduces the risk of postpartum hemorrhage. Physiological management is gaining popularity as it allows for delayed umbilical cord clamping, which benefits the newborn.
How Long Does it Take for the Placenta to Be Delivered?
The timing of placental delivery can vary:
- Physiological management: Up to 1 hour after birth for the placenta to deliver spontaneously
- Active management: The placenta typically delivers within 5-15 minutes after birth
If the placenta has not delivered within a certain time frame (30-60 minutes), this is considered a retained placenta and may require interventions to remove it.
What Happens to the Placenta After Birth?
After the placenta is delivered, it is carefully examined by healthcare providers to ensure it is intact. The umbilical cord is clamped and cut, separating the placenta from the newborn.
In most cases, the placenta is simply disposed of as medical waste. However, some families choose to keep the placenta for cultural reasons or to eat the placenta through placentophagy.
If the placenta appears abnormal or fragments are missing, it will be sent for pathology testing to assess for potential problems that could impact the newborn.
How Long Does it Take for the Placenta to Stop Working?
Although the placenta delivers shortly after birth, it does not immediately stop functioning.
After delivery, the placenta continues to remain alive and is able to:
- Provide oxygen and nourishment to the newborn for a short time
- Filter waste products out of the newborn’s bloodstream
This is why delayed umbilical cord clamping of at least 30-60 seconds is recommended. Allowing blood flow between the placenta and newborn to continue temporarily provides added blood volume and iron stores for the baby.
However, the placental circulation rapidly slows down and the organ becomes non-functional within 5-15 minutes after delivery.
The placenta is no longer alive or providing support to the newborn by this point. It is a discharged organ.
What Factors Affect How Long the Placenta Functions After Birth?
A few key factors impact how long the placenta remains functional after delivery:
- Umbilical cord clamping time: Delayed clamping allows the placenta to remain active longer, while immediate clamping stops placental transmission sooner.
- Method of placenta delivery: With active management, oxytocin given soon after birth causes the placenta to detach and degenerate faster.
- Maternal blood loss: Hemorrhage during delivery reduces blood flow between the placenta and uterus, causing it to cease function sooner.
- Placental abnormalities: Issues with placental implantation or development may shorten its viable lifespan after delivery.
In most normal vaginal deliveries with delayed cord clamping, the placenta remains functional for 3-15 minutes. But this window may be shorter or longer depending on circumstances.
How Long Does it Take for the Placenta to Physically Deteriorate?
Although the placenta stops functioning within minutes of birth, the physical organ itself takes much longer to deteriorate.
After delivery, the placental tissue is still alive with active cells. However, it is no longer supported by maternal blood circulation.
Over the next 24-48 hours, the cells in the placenta will die off due to:
- Loss of oxygen supply
- Loss of nutrients
- pH changes
- Buildup of waste
This process is known as placental necrosis. The tissue begins breaking down and the placenta progressively degenerates over this timeframe.
By 24-72 hours after delivery, the placenta is mostly necrotic tissue and well on its way to complete deterioration. However, the breakdown process continues over the next several days to weeks as the tissue is reabsorbed.
Placental Deterioration Timeline
- 0-15 minutes: Placental circulation stops, but tissue remains alive
- 24-48 hours: Widespread cell death and necrosis
- 72 hours: Largely necrotic tissue
- 1-2 weeks: Softening and breaking down of tissue
- 2-4 weeks: Nearly complete reabsorption and disintegration
Within about 4 weeks, the placenta is generally completely deteriorated through natural processes without any remnants left behind.
Does any Placental Tissue Remain After Delivery?
While most of the placenta detaches and delivers as a whole unit shortly after childbirth, small fragments can sometimes remain in the uterus.
Reasons placental tissue may remain include:
- Abnormally firm placental implantation sites
- Placenta acreta spectrum disorders
- Tearing of fragile placental tissue during delivery
- Manual removal techniques disturbing fragments
If small pieces of placental tissue remain attached to the uterus, they will still undergo necrosis and reabsorption in the days following birth.
However, retained placental fragments can increase the risks of:
- Postpartum hemorrhage
- Infection
- Uterine adhesions
For this reason, the uterus is closely monitored after delivery to ensure all placental tissue has detached and any remnants are identified early.
Does the Placenta Ever Persist After Birth?
In extremely rare cases, a significant portion of placental tissue may remain functionally attached after delivery. This is known as a persistent or retained placenta.
This occurs when the placenta continues to receive an adequate blood supply from abnormally invasive placental attachments. Parts of the organ essentially remain “alive” and functioning.
A persistent placenta may secrete hormones and bleed for days to weeks after birth. Eventually necrosis and reabsorption will occur, but very slowly.
This rare condition requires medical management to prevent complications like hemorrhage and to hasten placental deterioration.
Key Takeaways
- The placenta begins developing around week 2 of pregnancy and is fully formed by weeks 10-12.
- It is delivered within an hour of birth, either before or after the newborn.
- The placenta remains alive and provides oxygen/nutrients for around 5-15 minutes after delivery.
- It takes 24-48 hours for widespread placental cell death to occur.
- Over 2-4 weeks, the tissue fully deteriorates and is reabsorbed.
- Rarely, placental fragments may remain or the placenta may persist longer.
While the placenta is only a temporary organ, it provides essential support to the developing fetus. Understanding how long it remains functional and breaks down after delivery provides insight into fetal development and postpartum recovery.
| Timeline | Placental Changes |
|---|---|
| 0-15 minutes after birth | Circulation stops, but tissue remains alive |
| 24-48 hours after birth | Widespread cell death and necrosis |
| 72 hours after birth | Mostly necrotic tissue |
| 1-2 weeks after birth | Breaking down of tissue |
| 2-4 weeks after birth | Nearly complete deterioration and reabsorption |