Placental Abnormalities

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Implantation Issues - Sticky Situations

  • Placenta Previa: Implantation in lower uterine segment over/near internal os.
    • Types: Marginal, Partial, Complete. Low-lying: placenta edge within 2 cm of internal os.
    • Risk factors: Prior C-section, multiparity, advanced maternal age (AMA), smoking.

    ⭐ Painless, causeless, recurrent vaginal bleeding in 3rd trimester.

    • Diagnosis: Transvaginal sonography (TVS) is gold standard. ⚠️ Avoid per-vaginal examination.
  • Placenta Accreta Spectrum (PAS): Abnormal adherence/invasion of chorionic villi into myometrium.
    • Accreta: Villi attach to myometrium.
    • Increta: Villi invade into myometrium.
    • Percreta: Villi penetrate through myometrium, may invade adjacent organs (e.g., bladder).
    • Risk factors: Prior C-section (especially with anterior previa), placenta previa, AMA.
    • Diagnosis: Ultrasound (loss of retroplacental clear space, placental lacunae), MRI for posterior placenta/suspected percreta.
  • Vasa Previa: Fetal vessels run near internal os, unprotected by placenta/umbilical cord. Rupture leads to fetal exsanguination.
    • Associated with velamentous cord insertion, bilobed/succenturiate lobe placenta.
    • Diagnosis: Antenatal USG with color Doppler. Apt test/Ogita test on vaginal blood.

Shape & Cord Capers - Odd Ones Out

  • Abnormal Lobes/Shape:
    • Succenturiate Lobe: Accessory placental lobe; risk of retained tissue, Post-Partum Hemorrhage (PPH). Vasa previa and succenturiate lobe
    • Placenta Spuria: Detached accessory lobe, no connecting vessels.
    • Circumvallate Placenta: Fetal membranes fold back on fetal surface; ↑risk of abruption, IUGR, Preterm Delivery (PTD). Normal vs. Circumvallate Placenta Diagram
    • Circummarginate Placenta: Similar, but flat transition; less clinically significant.
  • Cord Insertion Anomalies:
    • Battledore Placenta: Marginal cord insertion. Usually benign. Anatomical Variations of the Placenta
    • Velamentous Insertion: Cord inserts into membranes; fetal vessels unprotected. Velamentous Cord Insertion and Vasa Previa

    ⭐ Velamentous cord insertion is associated with vasa previa and carries a high risk of fetal exsanguination if vessels rupture.

    • Vasa Previa: Fetal vessels run over or near internal cervical os. High risk of rupture & fetal exsanguination.
  • Knots:
    • False Knots: Benign; blood vessels appear as knots.
    • True Knots: Rare; risk of fetal compromise/demise if tightened.

Abruption Alert - Sudden Separation

Revealed vs Concealed Placental Abruption

  • Premature separation of normally implanted placenta after 20 weeks gestation.
  • Classic triad: Sudden-onset painful vaginal bleeding, uterine tenderness/hypertonicity (tetany), fetal distress.
    • Bleeding can be revealed, concealed, or mixed.
  • Risk Factors: Maternal HTN (most common), trauma, smoking, cocaine, prior abruption, PPROM, polyhydramnios with rapid decompression.
  • Complications: Maternal (DIC, shock, renal failure, Couvelaire uterus), Fetal (hypoxia, IUGR, prematurity, demise).

⭐ Concealed hemorrhage in placental abruption can lead to underestimation of blood loss and severe maternal/fetal compromise, including Couvelaire uterus (uteroplacental apoplexy).

Postpartum Placenta Problems - Lingering Issues

  • Retained Placenta:
    • Definition: Not expelled: 30 mins (active management), 60 mins (physiological).
    • Causes: Uterine atony, trapped placenta (closed cervix), placenta accreta spectrum.
    • Management: Controlled cord traction (CCT), IV oxytocin. Failure: manual removal (anesthesia).
    • Complications: Primary PPH, endometritis, Asherman's syndrome (rare).
  • Retained Placental Fragments (RPOC):
    • Small placental pieces in uterus post-delivery.
    • Symptoms: Secondary PPH (most common; bleeding >24h to 6-12 wks), uterine subinvolution, persistent foul lochia, low-grade fever.
    • Diagnosis: Ultrasound (USG) showing endometrial mass/thickening >10-15mm, often with ↑vascularity.
    • Management: Uterotonics, antibiotics (if infection suspected), D&C or hysteroscopic removal.

    ⭐ The most common cause of secondary PPH is retained placental fragments. Ultrasound of retained products of conception OR medical illustration of manual placenta removal)

  • Placental Polyp:
    • Late complication: organized retained placental tissue forming a vascular endometrial mass/polyp.
    • Symptoms: Intermittent or persistent abnormal vaginal bleeding, often weeks/months postpartum.
    • Diagnosis: USG (color Doppler helpful), sonohysterography, direct visualization via hysteroscopy.
    • Management: Hysteroscopic resection or D&C cautious of uterine perforation.

High‑Yield Points - ⚡ Biggest Takeaways

  • Placenta previa: Painless bright red bleeding in late pregnancy; ultrasound for diagnosis; avoid PV exam.
  • Abruptio placentae: Painful vaginal bleeding, tender, rigid uterus; associated with hypertension, trauma.
  • Placenta accreta spectrum: Abnormal adherence to myometrium; previous C-section is a major risk; high risk of massive PPH.
  • Vasa previa: Fetal vessels over internal os; painless bleeding at ROM with fetal bradycardia.
  • Succenturiate lobe: Risk of retained placental tissue leading to PPH.
  • Velamentous cord insertion: Unprotected vessels; risk of rupture and fetal hemorrhage.

Practice Questions: Placental Abnormalities

Test your understanding with these related questions

A 29-year-old G3P2 woman at 34 weeks' gestation is involved in a serious car accident, loses consciousness briefly, and presents to the emergency department awake and alert with a severe headache, abdominal, and pelvic pain. Her vital signs include a blood pressure of 150/90 mm Hg, heart rate of 120/min, temperature of 37.4°C (99.3°F), and respiratory rate of 22/min. Fetal heart rate is 155/min. Physical examination reveals minor bruises on the abdomen and limbs, blood in the vault upon vaginal inspection, and strong, frequent uterine contractions. Which of the following is most likely a complication of her current condition?

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Flashcards: Placental Abnormalities

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_____ syndrome is a manifestation of severe preeclampsia that presents with hemolysis, elevated liver enzymes, and low platelets

TAP TO REVEAL ANSWER

_____ syndrome is a manifestation of severe preeclampsia that presents with hemolysis, elevated liver enzymes, and low platelets

HELLP

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