Harvey's Garden

Abnormal labor and delivery

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  • Definition
    • Abnormally slow or arrested progression of labor. It is the leading indication for primary C-section.
    • Dystocia is broadly categorized by problems with the 3 “P’s”:
      • Power: Inadequate uterine contractions.
      • Passenger: Fetal size or position.
      • Passage: Maternal pelvis is too small.
  • Diagnosis of Labor Stages & Abnormalities
    • First Stage: Onset of labor to complete cervical dilation (10 cm).
      • Latent Phase (0-6 cm):
        • Protraction: >20 hrs (nulliparous) or >14 hrs (multiparous).
        • Tx: Therapeutic rest (analgesia), oxytocin, or amniotomy.
      • Active Phase (6-10 cm):
        • Protraction: Cervical change <1.2-1.5 cm/hr.
        • Arrest: No cervical change for ≥4 hours with adequate contractions OR ≥6 hours with inadequate contractions despite oxytocin. Adequate contractions are defined as >200 Montevideo units (MVUs).
        • Tx: Amniotomy and/or Oxytocin augmentation are primary treatments. C-section is indicated for arrest unresponsive to oxytocin.
    • Second Stage: Complete dilation to fetal delivery.
      • Arrest: Duration without an epidural is >2 hrs (multiparous) or >3 hrs (nulliparous). Add 1 hour to these times if an epidural is in use.
      • Tx: Reassess the “3 P’s.” Consider assisted vaginal delivery (forceps, vacuum) or C-section. Manual rotation can be attempted if the fetus is in an occiput posterior position.
    • Third Stage: Fetal delivery to placental delivery.
      • Protraction/Arrest: >30 minutes.
      • Tx: Uterotonics (e.g., oxytocin infusion), controlled cord traction. If these fail, manual extraction of the placenta is necessary.
  • Etiologies & Management (The 3 “P’s”)
    • 1. Power (Uterine Contractions)
      • Hypotonic contractions (<200 MVUs) are the most common cause of protraction/arrest.
      • Tx: Oxytocin administration is the key intervention to augment labor. An intrauterine pressure catheter (IUPC) can be placed to quantify contraction strength accurately.
    • 2. Passenger (Fetal Factors)
      • Malposition: Persistent occiput posterior (OP) position is most common. Causes severe back labor and prolonged second stage. Can be managed with manual rotation.
      • Malpresentation: Breech, face, brow, or shoulder presentation often requires C-section.
      • Macrosomia: Fetal weight >4000-4500g. Major risk factor for shoulder dystocia.
      • Shoulder Dystocia: OBSTETRIC EMERGENCY. Anterior shoulder becomes impacted behind the pubic symphysis after delivery of the head (“turtle sign”).
        • Management (HELPERR Mnemonic):
          • Help: Call for senior OB, anesthesia, and pediatrics.
          • Episiotomy: To create more room for maneuvers.
          • Legs: McRoberts maneuver (hyperflexion of maternal hips) is the first step and often successful.
          • Pressure: Apply suprapubic pressure (NOT fundal pressure).
          • Enter maneuvers: Internal rotation (e.g., Rubin, Woods corkscrew).
          • Remove posterior arm: Grasp the posterior arm and sweep it across the chest to deliver it.
          • Roll the patient: Move to “hands and knees” (Gaskin maneuver).
    • 3. Passage (Pelvic Factors)
      • Cephalopelvic Disproportion (CPD): A true disparity between the size of the fetal head and the maternal pelvis. This is a diagnosis of exclusion made after an adequate trial of labor with oxytocin fails.
      • Management: Requires C-section.
  • Key Complications
    • Maternal and/or fetal distress.
    • Increased risk of chorioamnionitis with prolonged rupture of membranes.
    • Postpartum hemorrhage.
    • Fetal injury, such as brachial plexus palsy or clavicular fracture, from shoulder dystocia.
    • Uterine rupture.

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