Placenta Previa

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    • Placenta Previa
      • A condition in which the placenta is implanted in the immediate vicinity of the cervical os. (MCQ)
      • Third trimester bleeding(MCQ)
        • Painless bleeding = previa
        • Painful bleeding = abruption
      • It can be classified into four types:
        • Complete placenta previa:
          • The placenta covers the entire internal cer- vical os
        • Partial placenta previa:
          • The placenta partially covers the internal cervical os.
        • Marginal placenta previa:
          • One edge of the placenta extends to the edge of the internal cervical os.
        • Low-lying placenta: (MCQ)
          • Within 2 cm of the internal cervical os.
      • Etiology
        • Unknown, but associated with: (MCQ)
          • High parity.
          • Older mothers.
          • Previous abortions.
          • Previous history of placenta previa.
          • Fetal anomalies.
        • Five to ten percent associated with placenta accreta, especially if prior low transverse cesarean section. (MCQ)
      • Clinical presentation
        • Painless, profuse bleeding in second or third trimester. (MCQ)
        • Postcoital bleeding.
        • Spotting during first and second trimester that subsides, and then recurs later in pregnancy.
      • Diagnosis
      • Transabdominal US (95% accurate). (MCQ)
      • MRI findings:
        • Placenta previa is diagnosed on MRI when it is low lying and partially or completely covering the internal os.
        • It is best demonstrated on sagittal images.
      • When US reveals that a baby is lying transversely,you should suspect Placenta previa(MCQ)
      • Double setup exam:
        • Take the patient to the operating room and prep for a C-section.
        • Do speculum exam:
        • If there is local bleeding, do a C- section; if not, palpate fornices to determine if placenta is covering the os.
        • The double setup exam is performed only on the rare occasion that the US is inconclusive and there is no MRI.
      • Management
        • Cesarean delivery is indicated for placenta previa. (MCQ)
    • Fetal Vessel Rupture(MCQ)
      • Two conditions cause third-trimester bleeding resulting from fetal vessel rupture
        • vasa previa
        • velamentous cord insertion
      • These two conditions often occur together and can cause fetal hemorrhage and death very quickly.
        • Vasa previa
          • A condition in which the unprotected fetal cord vessels pass over the internal cervical os, making them susceptible to rupture when mem- branes are ruptured. (MCQ)
        • Velamentous cord insertion(MCQ)
          • Fetal vessels insert in the membranes and travel unprotected to the placenta.
          • This leaves them susceptible to tearing when the amniotic sac ruptures.
          • The vessels are usually covered by Wharton’s jelly in the umbilical cord until they insert into the placenta.
          • Incidence: 1% of singletons, 10% of twins, 50% of triplets.
      • Clinical presentation
        • Vaginal bleeding with fetal distress.
      • Management
        • Correction of shock and immediate delivery (usually cesarean delivery).
    • Uterine Rupture
      • The disruption of the uterine musculature through all of its layers, usually with part of the fetus protruding through the opening.
      • Complications
        • Maternal: Hemorrhage, hysterectomy, death.
        • Fetal: Permanent neurologic impairment, cerebral palsy, death.
      • Risk factors
        • Prior uterine scar from a cesarean delivery is the most important risk factor:
          • Vertical scar: 10% risk due to scarring of the active, contractile portion of the uterus. (MCQ)
          • Low transverse scar: 0.5% risk.
        • Can occur in the setting of trauma.
      • Presentation and diagnosis
        • Nonreassuring fetal heart tones or bradycardia: Most suggestive of uteine rupture. (MCQ)
        • Sudden cessation of uterine contractions.
        • “Tearing” sensation in abdomen.
        • Presenting fetal part moves higher in the pelvis.
        • Vaginal bleeding.
        • Maternal hypovolemia from concealed hemorrhage.
      • Management
        • Immediate laparotomy and delivery. (MCQ)
        • May require a cesarean hysterectomy if uterus cannot be reconstructed.

      Placenta previa
      One in 200 pregnancies will be affected by this conditon. Consultant obstetrician Des Holden discusses the risks and complications of placenta previa
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      FINAL DVD Emergency C Section for a Bleeding Placenta Praevia,Surigao,Mindanao Feb,2013
      SIMPLIFIED SURGERY USING A NEW SET OF SURGICAL INSTRUMENTS FOR PLACENTA PREVIA ACCRETA
      SIMPLIFIED SURGERY USING A NEW SET OF SURGICAL INSTRUMENTS FOR THE MANAGEMENT OF PLACENTA PREVIA ACCRETA, INCRETA AND PERCRETA.

      The surgical technique and new surgical instruments employed are of great utility, as evidenced by the reduced bleeding and few trans-surgical complications.
      Rescue 911 – Episode 303 – “911 Placenta Previa”
      A woman with placenta previa has labor complications while home alone with her four-year-old daughter. This segment was taken from Episode 303 which aired on October 1, 1991 on CBS.

      Video Placenta Previa
      Obstetric U/S 4 – breech, placenta previa
      Examples of breech, vertex, placenta previa