Placenta accreta

Learning objectives

• Definition of placenta accreta spectrum
• Anesthetic management of placenta accreta

Definition and mechanisms

• Refers to a severe pregnancy complication that occurs when the placenta grows too deeply into the uterine wall
• With placenta accreta, part or all of the placenta remains attached after delivery, thereby possibly leading to severe blood loss after delivery
• Is considered a high-risk pregnancy complication
• Three types:
  • Placenta accreta: 
    • Placental villi adhere to the myometrium
    • Placenta does not pass through the wall of the uterus and does not impact the uterine muscles
    • Majority of cases
  • Placenta increta:
    • Invasion of the myometrium
    • Placenta does not pass through the uterine wall
    • 15-18% of cases
  • Placenta percreta:
    • Invasion through the myometrium to the serosa and surrounding organs
    • Might impact other organs such as the bladder or intestines
    • Most severe
    • 5-7% of cases

Signs and symptoms

• Often no signs or symptoms
• Although vaginal bleeding during the third trimester might occurs

Risk factors

• Previous uterine surgery or caesarean section
• Placenta position: if the placenta partially or totally covers the cervix (placenta previa) or sits in the lower portion of the uterus
• Maternal age > 35 years
• Multiparity
• IVF

Complications

• Major vaginal bleeding
• Thromboembolism
• Coagulopathy
• Anemia
• Premature birth
• Amniotic fluid embolism
• Damage to the uterus and surrounding organs
• Loss of fertility due to a hysterectomy
• Acute transfusion reaction
• Acute respiratory distress syndrome (ARDS)
• Acute kidney injury
• Infection
• Multisystem organ failure

Diagnosis

• Ultrasound
• MRI

Management

• Planning for delivery
  • Obstetricians will plan delivery between 35+0 and 36+6 weeks gestation in women stringy suspected to have placenta accreta
  • Administer a single course of antenatal glucocorticoids between 34 and 36 weeks of gestation
  • Symptoms of bleeding or preterm labor may hasten the need for delivery

Suggested reading

• Reale, S.C., Farber, M.K., 2022. Management of patients with suspected placenta accreta spectrum. BJA Education 22, 43–51.
• Silver RM, Barbour KD. Placenta accreta spectrum: accreta, increta, and percreta. Obstet Gynecol Clin North Am. 2015;42(2):381-402.

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