Retained placenta is a complication that can occur after vaginal or cesarean delivery, where the placenta fails to detach from the uterine wall. This can lead to postpartum hemorrhage and other complications if not managed properly. In a cesarean delivery, retained placenta may occur slightly more often than in vaginal deliveries. Let’s take a closer look at the incidence, risk factors, and management of retained placenta after a C-section.
Incidence of Retained Placenta after C-Section
Studies report the incidence of retained placenta after cesarean section to be around 1-3%. This is higher than the rate after vaginal deliveries, which is around 0.5-1%. Some key points on the incidence:
- A study of over 30,000 deliveries in the UK found an incidence of 2.1% for retained placenta after cesarean compared to 0.9% after vaginal delivery.
- A US study of over 87,000 deliveries found a retained placenta rate of 1.3% for cesarean sections and 0.7% for vaginal births.
- Emergency cesareans may have a higher risk than planned cesareans. One study found retention rates of 1.6% for planned and 2.5% for emergency c-sections.
- The general consensus is that retained placenta occurs 1-2 times more frequently after cesarean compared to vaginal delivery.
So while not extremely common, retained placenta does appear to complicate around 1-3% of cesarean deliveries. It’s important for obstetricians to be aware of risk factors and vigilantly examine the placenta after every delivery.
Risk Factors
Some factors can increase the risk of retained placenta after cesarean delivery. These include:
- Placenta previa – This is when the placenta covers part or all of the cervix. The placenta has an abnormal location and adherence in these cases.
- Placenta accreta – This is an abnormal adherence of the placenta to the uterine wall, which can make detachment difficult.
- Previous uterine surgery – Scarring from prior cesareans or other uterine procedures like myomectomy can alter attachment and make retention more likely.
- Labor abnormalities – Issues like prolonged labor, chorioamnionitis, preeclampsia have been linked to a higher risk.
- Emergency C-section – As mentioned, emergency procedures may carry a greater risk than planned ones.
- Multiparity – Women who have had multiple pregnancies seem to be at increased risk.
If any of these risk factors are present, extra care should be taken at the time of cesarean delivery to ensure complete placental removal. Using additional uterotonics like oxytocin after delivery may help prevent retention by promoting uterine contractions.
Diagnosis
Retained placenta is usually diagnosed when the placenta fails to deliver within 30 minutes after birth. Normal placental separation and detachment from the uterus occurs by 10-15 minutes after birth.
Signs that may indicate a retained placenta include:
- Failure of the placenta to deliver in a timely manner
- Continued bleeding from placental attachment site
- Uterine tone that fails to firm up after birth
- Umbilical cord that fails to show normal lengthening
- Placental fragments visible at cervix or vaginal canal
If retained placenta is suspected, several steps should be taken:
- Alert anesthesia team and have extra uterotonics like oxytocin ready
- Begin fundal massage to encourage uterine contractions
- Have instruments available for manual removal if needed
- Perform ultrasound to confirm diagnosis and location of placental remnants
- Prepare for potential blood transfusion if heavy bleeding occurs
Early recognition and preparation is key to safely managing retained placenta.
Management
When retained placenta is diagnosed after cesarean delivery, management focuses on stopping blood loss and removing any remaining placental tissue from the uterus. This is done either manually or medically:
Manual Removal
This involves the obstetrician entering the uterus and manually removing adherent pieces of the placenta. It is done either by:
- Reopening the hysterotomy incision from the cesarean
- Dilating the cervix digitally and entering through the vagina
Manual removal is often successful at clearing the uterus of all placental fragments under direct visualization. Complications like perforation or infection can occasionally occur.
Medical Management
If bleeding is minimal, the provider may opt to manage retained placenta medically without manual removal. This involves:
- Giving uterotonic medications like oxytocin, methylergonovine, carboprost to induce uterine contractions.
- Giving IV antibiotics to prevent infection.
- Carefully observing bleeding and clotting.
- Allowing the placenta to deliver spontaneously or resorbed over hours to days.
Studies show 50-80% success rate with this conservative method when bleeding is not severe. However, some placental tissue may remain in the uterus.
Which is Better?
There is debate over whether manual removal or conservative management has better outcomes for retained placenta after cesarean. Some key points:
- Manual removal may decrease the risk of delayed hemorrhage, infection, and need for re-operation.
- However, it also has higher risks like uterine perforation, fluid overload from rapid bleeding.
- Conservative management avoids surgical risks but up to 50% may still need delayed manual removal if placenta is not expelled.
- There are no definitive trials comparing the two approaches. Choice depends on clinical factors like stability, bleeding amount, provider experience.
In hemodynamically stable patients with minimal ongoing bleeding, a trial of uterotonics and observation may be reasonable. However, for heavy bleeding or unstable patients, prompt manual removal is likely the safest approach.
Complications
Retained placenta after cesarean section can lead to complications like:
- Hemorrhage – Excessive bleeding either immediately or in a delayed fashion. This is the most severe complication.
- Infection – Increased risk of endometritis, wound infection, sepsis.
- Blood transfusion – May be needed for blood loss replacement.
- Hysterectomy – Rarely needed as a life-saving measure for uncontrolled uterine bleeding.
- Adherence disorders – Placenta accreta spectrum if abnormal adherence was present.
- Reoperation – For delayed complications or placental remnants.
Thankfully, major complications are relatively uncommon with proper management. But prompt recognition and treatment of retained placenta is vital to minimizing risks.
Prevention
While not always possible, some measures can help reduce the risk of retained placenta after cesarean:
- Identify and manage high-risk conditions like placenta previa/accreta prior to delivery.
- Optimize placental location and adherence by avoiding unnecessary early elective cesareans.
- Use preventative oxytocin immediately after delivery to encourage placental separation.
- Gentle cord traction and uterine massage after delivery can aid placental detachment.
- Clear communication and preparation with anesthesia and nursing staff.
Despite best efforts, retained placenta may still occur. But being aware of risk factors and having proper protocols in place allows for rapid recognition and treatment.
Conclusion
In summary:
- Retained placenta complicates around 1-3% of cesarean deliveries.
- Risk is higher with placenta previa/accreta, prior uterine surgery, emergencies.
- Early recognition and preparation is key for optimal management.
- Manual removal or conservative measures may be used based on clinical factors.
- Prompt treatment helps prevent hemorrhage, infection and other complications.
- Understanding incidence, diagnosis and management is important for obstetric providers performing cesarean deliveries.
Retained placenta requires vigilance and appropriate intervention to optimize safety after cesarean section. Further research on prevention and best treatment practices is still needed.