II. Definition

  1. Abnormal Fetal Position with occiput at maternal Sacrum
  2. Fetal face towards maternal symphysis pubis

III. Epidemiology

  1. Represents 10% of Fetal Positions

IV. Physiology

  1. Less favorable fetal head diameter for delivery
    1. Deflexion of fetal head
    2. Posterior presentation
  2. Usually corrects spontaneously
    1. Rotates to Occiput Anterior position in 90% of cases

V. Symptoms

  1. Back labor
  2. Prolonged labor
    1. Nulliparous: Additional two hours
    2. Multiparous: Additional one hour

VI. Signs: Digital cervical exam

  1. Asymmetric cervical dilation
    1. Persistant anterior lip
  2. Palpation of fetal head
    1. Fetal anterior Fontanel most palpable
    2. Follow sagittal Suture to posterior Fontanel
    3. Posterior Fontanel, lambdoid Suture with be posterior

VII. Complications

  1. Failure to Progress
  2. Extended episiotomy or perineal Laceration

VIII. Management

  1. Spontaneous Delivery (anticipate in 45% of cases)
  2. Maternal position changes (unclear efficacy)
    1. Any position in which mother curls forward from hips
    2. Hands and knees
    3. Squatting
  3. Manual rotation during vaginal exam
    1. See Manual Rotation in Occipitoposterior Presentation
  4. Vacuum Delivery
    1. Place vacuum cup as posterior as possible
      1. Inproves flexion of fetal head
    2. Do not use vacuum to rotate fetal head
      1. Results in Scalp Laceration
  5. Forceps Delivery
  6. Forceps Rotation (skilled clinician only)
    1. Techniques: Scanzoni or Kielland
    2. Requires immediate Ceserean back-up
    3. Rarely performed in U.S. now

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