Estimated reading time: 4 minutes
A retained placenta isn’t just an inconvenience; it can be a life-threatening situation if not anticipated and managed early. It’s one of those scenarios where a missed history, a missed scar, or a delayed decision can change the entire outcome for both mother and baby.
In this blog, we’ll break down the key risk factors, share a real-life case that highlights the importance of thorough history-taking, and give you practical clinical tips you can apply in labour rooms and theatres.
Understanding the Placenta & Retained Placenta
The placenta is a temporary but essential organ formed during pregnancy. It provides oxygen and nutrients to the baby, takes away waste products, and produces crucial hormones. In normal circumstances, after delivery, the uterus tightens and the placenta separates spontaneously within 30 minutes.
But if the placenta does not deliver fully or even partially within 30 minutes postnatally, it’s referred to as a retained placenta. This is not a mere delay — it can result in catastrophic postpartum hemorrhage (PPH), infection, and higher maternal morbidity if it is not identified and treated early.
1) Risk Factors Related to Poor Uterine Contraction (Uterine Atony)
When the uterus doesn’t contract properly after delivery, the placenta often refuses to separate. Some common triggers are:
- High parity — overstretched uterine muscle
- Prolonged or excessive oxytocin use → receptor fatigue leading to atony
- Multiple gestation / uterine over-distension
- General uterine atonicity — remember, atony can cause both PPH and retained placenta.
Clinical insight: Epidural analgesia has been loosely linked to impaired uterine tone. While not a documented risk factor, don’t ignore it completely in suspicious cases.
2) Risk Factors Related to Abnormal Placentation
Sometimes, the placenta adheres too firmly to the uterine wall, making separation tricky or impossible:
- Previous uterine surgeries — e.g., myomectomy, D&C, hysteroscopy
- IVF conceptions — higher risk of abnormal implantation
- Low-lying placenta or previa
- Any prior intervention that alters the endometrial–myometrial interface
Remember: Even in primary patients with no previous cesarean, morbid adherence can happen if there’s a hidden surgical history.
3) Other Important Risk Factors
- Preterm deliveries — incomplete placental maturity may lead to retention
- Congenital uterine anomalies
- Previous history of retained placenta or manual removal
- Past PPH events — always ask about manual separation or heavy bleeding during previous deliveries.
A Real Case That Changed Our Approach
At AIIMS, we once managed a patient with a high-risk pregnancy who presented with pre-viable PPROM. She was a primary patient, highly educated, and under close monitoring. At 26 weeks, an emergency cesarean was performed — unfortunately, the baby couldn’t be saved due to extreme prematurity.
But here’s where the case became a teaching point:
We later discovered she had undergone a myomectomy years earlier. This crucial history was missed — and so was the abdominal scar during initial examinations. When a focused MRI was finally done, it revealed a focal accreta at the previous scar site.
Because we identified it late, the situation became extremely complex. We had to prepare uterine artery balloons and perform a focal resection of the placenta. It was a tough call, but the patient survived.
Lesson learned:
- Always examine for scars — don’t assume there’s no history just because the patient says so.
- Always dig deeper into past surgeries, even minor ones.
- A single missed detail can flip a “routine” case into a high-risk obstetric emergency.
Practical Clinical Tips
Here’s a quick checklist to keep handy in your labour room:
- Take a complete history — previous uterine surgeries, ART conceptions, retained placenta, manual removal, or PPH.
- Inspect the abdomen — even subtle scars can guide your risk assessment.
- Use imaging wisely — targeted ultrasounds and MRIs can help detect morbid adherence early.
- Be prepared for hemorrhage — anticipate balloon tamponade, uterotonics, embolisation, or even hysterectomy if needed.
- Document everything — record any retained placenta episodes for safer future pregnancies.
- Train with mock drills — rehearsed teams manage emergencies better.
Key Takeaways
- Retained placenta often stems from uterine atony or abnormal placentation — identify which applies to your patient early.
- Never skip history-taking — an old scar can hold the key to preventing catastrophe.
- Always anticipate and prepare for heavy bleeding when risk factors are present.
Smart preparation saves lives. Every. Single. Time.
