Uterine Placenta Accreta - Symptoms, Causes, Treatment & Prevention

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Overview

Placenta accreta is a serious obstetric condition in which the placenta grows too deeply into the wall of the uterus and fails to separate normally after delivery. The term “uterine placenta accreta” is used to emphasize that the abnormal attachment occurs within the uterine myometrium.

When the placenta implants normally, a thin layer of decidua (the uterine lining) separates it from the muscular wall. In placenta accreta, this decidual layer is absent or deficient, allowing the chorionic villi (the placental tissue) to attach directly to the myometrium. The condition exists on a spectrum:

• Placenta accreta – villi attach to the myometrium.
• Placenta increta – villi invade into the myometrium.
• Placenta percreta – villi penetrate through the uterine serosa and may involve adjacent organs (bladder, bowel).

Placenta accreta is most common in women who have had previous uterine surgery, particularly cesarean delivery. It is a leading cause of severe postpartum hemorrhage and maternal morbidity.

Who it affects

• Women of reproductive age, typically diagnosed in the second or third trimester.
• Incidence rises sharply with the number of prior cesarean sections: about 0.2 % after one cesarean, 3 % after two, and up to 11 % after three or more [CDC, 2023].
• Also more common in women with a history of uterine curettage, myomectomy, or placenta previa.

Prevalence

In the United States, placenta accreta is estimated to affect ~1 in 533 pregnancies (0.19 %). The global rate is rising in parallel with increasing cesarean delivery rates, currently estimated at 1‑2 per 1,000 births in high‑income countries [WHO, 2022].

Symptoms

Placenta accreta often does not produce noticeable symptoms before delivery, which is why routine ultrasound screening in high‑risk pregnancies is essential. When symptoms do appear, they may include:

• Abnormal vaginal bleeding – especially after 20 weeks gestation or following any vaginal exam.
• Painful uterine cramping that does not subside with rest.
• Bright red or dark brown discharge in the second half of pregnancy.
• Early signs of labor (contractions, dilation) that occur before the due date without a clear cause.
• Persistent uterine tenderness on physical examination.
• Presence of placenta previa on imaging—placenta covering the cervical os is a red flag for accreta.

Most patients are asymptomatic until delivery, when the placenta fails to separate, leading to massive bleeding.

Causes and Risk Factors

The exact cause of placenta accreta is not fully understood, but it is believed to result from defective decidualization (formation of the normal uterine lining) and excessive trophoblastic invasion.

Key risk factors

• Prior cesarean delivery – each additional scar raises risk dramatically.
• Placenta previa – especially when combined with previous uterine surgery.
• Uterine curettage or dilation & curettage (D&C) procedures.
• Uterine fibroids or adenomyosis that alter normal endometrial architecture.
• Advanced maternal age (≥35 years).
• Multiparity (having given birth three or more times).
• Previous uterine surgery such as myomectomy, hysteroscopic polypectomy, or uterine ventouse delivery.
• Assisted reproductive technology (ART) – some studies suggest a modest increase in risk.

Genetic predisposition has not been clearly identified, but ongoing research is exploring the role of placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) pathways.

Diagnosis

Early detection is crucial to reduce maternal morbidity. Diagnosis relies on a combination of clinical suspicion, imaging, and occasionally histopathology after delivery.

Ultrasound (first‑line)

• Transabdominal and transvaginal sonography can reveal loss of the normal hypoechoic retroplacental zone, placental lacunae (vascular spaces), and focal myometrial thinning.
• Color Doppler shows turbulent blood flow at the placental‑myometrial interface.

Magnetic Resonance Imaging (MRI)

• Reserved for ambiguous cases or when posterior placental location limits ultrasound view.
• Provides detailed assessment of depth of invasion and involvement of adjacent structures (e.g., bladder).

Laboratory studies

• Complete blood count (CBC) and coagulation profile to establish baseline before planned delivery.
• Type and screen for blood transfusion planning.

Intra‑operative findings

When the placenta does not separate after delivery, the surgeon may note a “bulky” or “firm” attachment, prompting suspicion of accreta. Histologic examination of the uterus after hysterectomy confirms the diagnosis.

Screening recommendations

• All women with placenta previa and ≥1 prior cesarean should undergo targeted ultrasound at 18‑20 weeks.
• Repeat imaging at 28‑32 weeks if initial study is inconclusive.

Treatment Options

Management is individualized based on gestational age, severity (accreta vs. increta vs. percreta), desire for uterine preservation, and maternal comorbidities.

Planned delivery (gold standard)

• Timing – Delivery is usually scheduled at 34‑36 weeks to balance fetal maturity with the risk of spontaneous labor.
• Cesarean hysterectomy – The most common definitive treatment: delivery of the baby via cesarean, followed by immediate hysterectomy (removal of the uterus) without attempting placental separation. This approach markedly reduces hemorrhage.
• Uterine‑preserving surgery – In selected cases (desire for future fertility, limited invasion), surgeons may attempt placental removal with adjuncts such as uterine artery embolization, balloon occlusion catheters, or Bakri balloon tamponade.

Adjunctive techniques to control bleeding

• Prophylactic balloon occlusion of the internal iliac or uterine arteries (interventional radiology).
• Uterine artery embolization (UAE) – Post‑delivery embolization if bleeding persists.
• Tranexamic acid – Antifibrinolytic agent given intra‑operatively (10 mg/kg loading dose, then 1 mg/kg/h infusion) as per WHO recommendations.
• Recombinant factor VIIa – Reserved for refractory hemorrhage.
• Bakri or Foley balloon tamponade – Inflated inside the uterus to provide pressure.

Medications

• Corticosteroids (betamethasone 12 mg IM, 24 h apart) for fetal lung maturity if delivery is planned before 37 weeks.
• MgSO₄ for neuroprotection if delivery occurs before 32 weeks.
• Antibiotic prophylaxis (e.g., cefazolin 2 g IV) to reduce infection risk during surgery.

Post‑operative care

• ICU monitoring for hemorrhage, coagulopathy, and organ dysfunction.
• Blood product support – packed red cells, plasma, platelets as guided by labs.
• Early ambulation and thromboprophylaxis (low‑molecular‑weight heparin) unless contraindicated.

Living with Uterine Placenta Accreta

Even after definitive treatment, many women experience physical and emotional challenges. Below are practical tips for the recovery period and beyond.

Physical recovery

• Incision care – Keep the surgical site clean and dry; follow your surgeon’s suture removal schedule.
• Pain management – Use prescribed NSAIDs/acetaminophen; avoid NSAIDs if you have renal impairment.
• Bleeding watch – Light lochia is normal for 2‑3 weeks; soak >2 pads per hour or large clots should be reported.
• Pelvic floor exercises – Gentle Kegel exercises after 6 weeks (unless you had a hysterectomy with extensive pelvic dissection) to restore muscle tone.
• Nutrition – Iron‑rich foods (red meat, lentils, leafy greens) and vitamin C to aid iron absorption.

Emotional wellbeing

• Post‑partum depression is more common after traumatic deliveries; consider counseling or support groups.
• Discuss future fertility openly with your OB‑GYN; many women who retain their uterus can have a later pregnancy, but risk of recurrence is 5‑10 % and requires close monitoring.

Follow‑up schedule

• First postoperative visit 2‑3 weeks after discharge.
• Ultrasound at 6 weeks to assess healing if uterus was preserved.
• Annual pelvic exam and imaging only if new symptoms arise.

Prevention

Because many risk factors are related to prior uterine surgery, prevention focuses on minimizing unnecessary procedures.

• Limit cesarean deliveries – Strict indications, encourage trial of labor after cesarean (TOLAC) when safe.
• Careful use of D&C – Reserve for clear indications; consider medical management for early pregnancy loss when appropriate.
• Optimal management of placenta previa – Early ultrasound detection and appropriate timing of delivery reduce the need for emergent surgery.
• Pre‑conception counseling for women with known uterine scars; discuss risks and alternative delivery plans.
• Weight management and control of chronic conditions (diabetes, hypertension) – May indirectly reduce the need for repeat cesareans.

Complications

If placenta accreta is not identified early or managed inadequately, serious complications can arise:

• Severe postpartum hemorrhage – leading to hypovolemic shock.
• Need for massive transfusion – >10 units of packed red cells in some cases.
• Coagulopathy and disseminated intravascular coagulation (DIC).
• Organ injury – bladder or ureteral damage in percreta cases.
• Infection – Endometritis, wound infection, sepsis.
• Infertility – Hysterectomy eliminates future childbearing.
• Maternal mortality – Estimated 5‑7 % in severe percreta cases [WHO, 2022].

When to Seek Emergency Care

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Sources: Mayo Clinic, Centers for Disease Control and Prevention (CDC), National Institutes of Health (NIH), World Health Organization (WHO), Cleveland Clinic, American College of Obstetricians and Gynecologists (ACOG) Practice Bulletins, *Obstetrics & Gynecology* journal (2021‑2023). All information is for educational purposes and does not replace personalized medical advice.

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