Placental Abnormalities

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).
  • Placenta Spuria: Detached accessory lobe, no connecting vessels.
  • Circumvallate Placenta: Fetal membranes fold back on fetal surface; ↑risk of abruption, IUGR, Preterm Delivery (PTD).
  • Circummarginate Placenta: Similar, but flat transition; less clinically significant.
• Cord Insertion Anomalies:
  • Battledore Placenta: Marginal cord insertion. Usually benign.
  • Velamentous Insertion: Cord inserts into membranes; fetal vessels unprotected.

  ⭐ 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

• 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. 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.