OB/GYN
Labor Management & Dystocia
OB/GYN

Labor Management & Dystocia

Stages of labor, arrest disorders, shoulder dystocia.

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◆Stages of labor

  • •First stage: onset of labor → 10 cm
  • • Latent phase: 0–6 cm (slow)
  • • Active phase: 6–10 cm (faster)
  • •Second stage: 10 cm → delivery of fetus
  • •Third stage: delivery of placenta (<30 min)
  • •Fourth stage: first hour postpartum (recovery)

◆Arrest disorders

  • •Latent arrest (0–5 cm): prolonged but doesn't mandate C/S; supportive
  • •ACTIVE phase arrest (≥6 cm + ROM + no change ≥4 h with adequate contractions OR ≥6 h with inadequate) → C-section
  • •Adequate contractions: ≥200 Montevideo units in 10 min, or 3–5 contractions/10 min
  • •Second stage arrest: head low (≥+2 station) → operative vaginal; high → C/S
  • •Augment first with OXYTOCIN if contractions inadequate

◆Operative vaginal delivery

  • •Indications: prolonged 2nd stage, maternal exhaustion, non-reassuring tracing, maternal cardiac condition limiting Valsalva
  • •Forceps vs vacuum (similar success; vacuum easier to use but ↑ cephalohematoma)
  • •Prerequisites: fully dilated, ROM, head at ≥+2, no malposition

◆Cesarean delivery indications

  • •Maternal: arrest of labor, severe preeclampsia (sometimes), HSV active lesions, placenta previa
  • •Fetal: non-reassuring tracing, malpresentation, multi-gestation (often), prior classical C/S
  • •VL ≥1000 in HIV+ mom

◆Shoulder dystocia

  • •Head delivered but anterior shoulder fails to deliver
  • •RFs: macrosomia, GDM, prolonged 2nd stage, prior dystocia
  • •HELPERR: Help, Episiotomy, Legs (McRoberts — hyperflex thighs to abdomen), Pressure (suprapubic), Enter rotational (Rubin, Wood's screw), Remove posterior arm, Roll patient (Gaskin/all-fours)
  • •AVOID fundal pressure (impacts shoulder further)
  • •Complications: brachial plexus injury, clavicle/humerus fracture, hypoxia

◆Tocolysis (preterm labor)

  • •Nifedipine (CCB): first-line for most
  • •Indomethacin: <32 weeks (premature ductus closure if used later)
  • •Magnesium sulfate: <32 weeks for neuroprotection
  • •Terbutaline: short-term only
  • •Goal: buy 48 hours for steroids
  • •Antenatal corticosteroids (betamethasone or dex) <34 weeks reduce NRDS, IVH, NEC
  • •GBS prophylaxis with PCN G if unknown or positive

◆Induction of labor

  • •Cervical ripening if unfavorable Bishop score: misoprostol (PGE1) or dinoprostone (PGE2), or mechanical (Foley)
  • •Oxytocin for augmentation
  • •Amniotomy as appropriate
  • •Contraindications: prior classical C/S, transverse lie, placenta previa, vasa previa

High-yield pearls

  • ◆≥6 cm + ROM + no change ≥4 h with adequate contractions = active phase arrest = C/S
  • ◆Inadequate contractions → augment with oxytocin FIRST
  • ◆Shoulder dystocia first move: McRoberts + suprapubic pressure
  • ◆Indomethacin contraindicated >32 weeks (premature ductus closure)
  • ◆Oxytocin → SIADH risk (ADH-like)
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