II. Definitions

  1. Brow Presentation
    1. Head hyperextended, with brow as presenting part

III. Pathophysiology

  1. Normal Attitude: Fetus is in full flexion
    1. Smallest fetal head diameter: Suboccipitobregmatic
  2. Brow Presentation is an extended attitude
    1. Results in largest head diameter: Occipitomental
    2. Increases diameter 3 cm (24%) over flexed head
    3. May results in Failure to Progress

IV. Epidemiology

  1. Incidence: 0.02% of singleton deliveries (1 in 1400 live births)

V. Causes

  1. Similar to Face Presentation

VI. Signs

  1. Digital cervical exam
    1. Forehead features palpable (anterior Fontanel, nose)

VII. Management

  1. Ceserean section required in most cases
  2. Brow Presentation rarely can deliver vaginally unless:
    1. Spontaneously converts to vertex or Face Presentation
    2. Fetus is very small or Pelvis is very large
  3. Do not attempt to convert Brow Presentation to vertex
  4. Never apply vacuum extractor to Brow Presentation
  5. Do not apply internal scalp electrodes
  6. Avoid Oxytocin

VIII. Complications

  1. Increased perinatal mortality: 1-8%

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