You might be surprised to learn that the birth of your baby doesn’t signal the end of the birth process.
Expulsion of placenta
The final stage of your birth will be the birth of your placenta. This is known as the third stage of labor.
The third stage of labor begins from the moment your baby is born to the birth of your placenta and membranes and the control of postpartum blood loss.
What causes placental expulsion?
Your placenta is an incredible organ that nourishes your baby during pregnancy.
Once your baby has been born safely, the job of the placenta is now complete and the body will work to expel it.
The placenta is the only organ in the body that is expelled after its work is done, which is pretty amazing.
After your baby is born, your uterus will continue to tighten and shrink to push the placenta off the wall of the uterus.
Following a normal separation, the placenta will fall down into the lower uterine segment and into the birth canal, ready to be expelled.
Methods of placental expulsion
You’ll be given two options for how you wish to birth your placenta.
They are :
- Physiological management (also known as expectant management). This means waiting for the placenta to be expelled naturally, without the use of medications
- Active management. This means you’ll be given medication to help contract the uterus and expel the placenta.
Which type of management?
Physiological (expectant) management
Physiological management of the third stage of labor involves facilitating spontaneous placental separation. It’s usually performed in low risk settings, such as birth centres or at home, following a normal vaginal birth.
After the birth of her baby, the mother’s oxytocin levels will remain high, continuing the process of uterine contractions.
The purpose of these tightenings now is to help the placenta separate from the uterine wall. Once it has separated naturally, it will drop down into the uterine cavity and move down into the birth canal, where it can be expelled naturally through the vagina.
This can be aided by gravity or maternal pushing, without the care provider pulling or touching the umbilical cord. This method is often recommended for low risk women, who are not at increased risk of increased vaginal bleeding or severe postpartum hemorrhage.
The process usually takes about 20-40 minutes but can take up to an hour.
Learn more about the physiological third stage by reading BellyBelly’s article The Third Stage Of Labor | Benefits Of A Natural Third Stage.
Active management involves being given what’s known as a uterotonic drug, which is a medication that acts to contract the smooth uterine muscle, to aid placental delivery.
This medication is an artificial version of your body’s natural oxytocin hormone and is usually given either intravenously through a drip, or as an injection.
Placental separation often occurs more quickly, due to the medication. Your care provider will look out for signs of complete separation before gently guiding your placenta out, using controlled cord traction.
This method is usually recommended for women who are at higher risk of having a postpartum hemorrhage; for example, women whose labors have been induced or following an assisted birth.
This method might also be recommended for you if you have certain health conditions or known blood disorders.
Mechanisms of placental separation
Birthing your placenta and controlling blood loss in the third stage are determined by a complex set of processes, controlled by hormones.
As the placenta begins to separate, a blood clot will form behind the placenta, between the uterine wall and the placenta. This is known as a retro-placental clot. It’s thought that the weight of this clot helps push the placenta off the uterine wall to complete its separation.
There are different methods of placental expulsion, determined by different bleeding patterns.
The Schultz method
The Schultz method occurs when separation begins at the centre of the placenta. This means that, as it separates, the fetal surface of the placenta (which looks shiny) will present first, from the center, and the rest will follow.
This is the most common method of placental expulsion.
The Duncan method
The Matthews Duncan method occurs when separation begins from the edge of the placenta. In this method, the whole placenta will slide down and out of the uterus sideways. The leading edge of the placenta and maternal surface presents first.
This method is less common, with only about 20% of placentas presenting in this way. It’s thought to result in more bleeding, resulting in its nickname, the ‘Dirty Duncan’.
In the Schultz method, as the placenta separates and presents from the middle, the retro-placental clot and any blood released is generally self contained within the membranes as the placenta is expelled.
In the Duncan method, however, separation happens more slowly, allowing more time for bleeding. As the placenta slips out sideways, the contents will spill out immediately, and are not contained in the same way.
Your health care providers will not know which method of placenta expulsion your body will follow; neither will they be able to change it.
Signs of placental separation
Once your baby is born, you’ll most likely be busy falling in love with your bundle of joy, and taking in every inch of your baby’s perfect little body. Your care provider, though, will still be keeping a watchful eye and looking out for clues that your body is ready to expel your placenta.
There are 3 signs of placenta separation:
- Cord lengthening. Once the placenta has separated and drops down in the uterine cavity or birth canal, you will see the visible section of the umbilical cord lengthen. This occurs as the placenta moves closer to the entrance of the vagina, bringing the cord with it
- A sudden gush of blood from the vagina. As the placenta separates, it’s important for the blood vessels to clamp down promptly to prevent excessive bleeding. During this process, it’s normal to experience a small gush of blood. Your care provider will inform you if this blood loss is heavier than expected. Remember, your body has already prepared for this blood loss. During pregnancy, your blood volume increases to meet the demands of your growing baby. A blood loss of up to 500 mls is considered normal during the third stage. In most healthy women, the body will be able to compensate well, without feeling the effects
- A firming of the fundus (top of the uterus). Your care provider might check the top of the uterus through the abdominal wall, to see if it feels firm. You can feel this for yourself, too. After birth, the uterus will already have shrunk in size. The top of the uterus is now likely to be somewhere between your belly button and the top of your pubic bone. It should feel round and firm, like a ball. The uterus needs to tighten like this, to seal off the open vessel that once supplied the placenta. This prevents you from losing too much blood. If the uterus is unable to tighten in this way, rapid blood loss will become problematic.
What happens if I have a cesarean birth?
During a cesarean birth, your doctor will need to remove the placenta from your uterus before closing the incision.
After the birth, it’s likely your doctor will perform something known as uterine massage. Massaging the uterus encourages uterine contraction, to help firm it up. If the uterus doesn’t firm up by itself, you might be given a medication to help. This will prevent postpartum hemorrhage.
Having skin to skin contact with your baby, putting your baby to the breast or stimulating the nipples in the immediate postpartum period are also ways to increase your natural oxytocin level and encourage uterine contraction.
You can find out more about this in C-Section Birth – What Happens In A Cesarean.
What happens if the placenta is not removed after birth?
Most care providers recommend birthing the placenta within 30-60 mins after your baby is born, depending on which method you choose (physiological or active management).
A prolonged third stage is known to increase the incidence of postpartum hemorrhage.
If your placenta doesn’t separate from the uterine wall following a vaginal birth, or does not come away completely within the desired amount of time, this is known as a retained placenta.
Find out more in Retained Placenta | Symptoms And Treatment.
What are the risks of a retained placenta?
A retained placenta is a major concern, as the uterus will not be able to clamp down effectively to control bleeding if the placenta is still in place.
If the placenta fails to come away in the third stage of labor, a mother is at risk of severe and dangerous bleeding, as well as infection.
If there is severe bleeding and postpartum hemorrhage (estimated blood loss over 500 mls) occurs, it might be necessary for a mother to receive blood transfusions to replace what has been lost.
In rare cases where bleeding cannot be controlled, a hysterectomy (removal of the uterus) might be required as a last resort to save a mother’s life.
Risk factors for retained placenta
Certain risk factors increase the likelihood of a retained placenta in the third stage of labor.
These risk factors include but are not limited to:
- Uterine atony (in other words, poor uterine tone). An atonic uterus with poor contraction might prevent normal placental separation and expulsion
- Placenta accreta spectrum (PAS). This includes placenta accreta, placenta increta and placenta percreta. Placenta accreta is a generalised term used to describe an abnormally adherent placenta, where the placenta grows too deeply within the wall of the uterus
- Prolonged use of synthetic oxytocin. This happens often in the case of induced labor
- Previous uterine surgery, including previous cesarean birth. Scarring on the uterine wall can increase the chances of your placenta attaching too deeply.
A previous retained placenta and congenital uterine abnormalities are also thought to be risk factors.
Manual removal of placenta
Sometimes, if the placenta does not separate naturally or with the aid of medication, manual placenta removal is required. Manual removal will also be required if the birth of the placenta is incomplete.
Whichever way you choose to birth your placenta, your care provider will inspect it to make sure it is all complete and that no sections of the placenta are missing.
If a part of the placenta remains inside the womb, it will not be able to shrink down effectively to clamp off the blood vessels that were supplying it. This will likely lead to excessive bleeding. Even if the uterus is able to shrink down in size, a mother is still at risk of postpartum hemorrhage, as the body will try to ‘flush out’ the remaining placenta, increasing the risk of heavy bleeding.
A manual removal of the placenta (sometimes referred to as MROP) is a surgical procedure, performed in theatre under general or spinal anaesthetic, to ensure you’re comfortable throughout the procedure.
Once you’re comfortable, the surgeon will carefully and painlessly remove your placenta. You might be given a course of prophylactic antibiotics to minimize the risk of developing an infection after the surgery.
Why do we give oxytocin after birth?
Synthetic oxytocin can be given after birth in the third stage of labor, for a number of reasons.
During active management of the third stage, oxytocin is given to expedite the birth of the placenta. It might be recommended to you if you have an increased risk of bleeding or if you have certain medical conditions, such as abnormal clotting factors.
Artificial oxytocin will attempt to mimic what your body does naturally, after birth, to encourage placental separation and the expulsion of the placenta.
Oxytocin can also be given following a physiological third stage, if placental separation appears to be ineffective or incomplete.
Oxytocin will also be recommended if you are losing too much blood after your birth, to prevent further complications.