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Cervical Ripening Agents

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Cervical Ripening Agents

  • See Also
  1. Cervical Ripening
  2. Labor Induction
  3. Dinoprostone
  4. Misoprostol
  • Indications
  1. Bishop Score <6
  2. Membranes intact
  3. No active contraction pattern
    1. Less than 10 mild contractions per hour
  • Contraindications
  1. Contractions >3 in 10 minutes prior to placement
  • Precautions
  1. Monitor Fetal Heart Rate and tocometry starting 15 to 30 minutes before, and for 30-120 minutes after placement
  1. Initiate Fetal Heart Rate and tocometry
    1. Start 15-30 minutes before gel inserted
    2. Continue monitoring for 30-120 minutes after
  2. Insertion Technique
    1. Use one syringe of gel (0.5 mg in 3cc KY)
    2. Introduce gel into Cervix
      1. Cervix not effaced: Use 20 mm catheter
      2. Cervix effaced 50% or greater: Use 10 mm catheter
      3. Intracervical is preferred over posterior fornix
        1. Perry (2004) Obstet Gynecol 103:13-7 [PubMed]
    3. Patient remains supine for 30 minutes
  3. Dosing
    1. Repeat every 6 hours up to 3 doses in 24 hours
  4. End points
    1. Bishop Score of 8 or greater
    2. Strong uterine contractions
  5. Drug Interactions
    1. Wait 6-12 hours before starting Pitocin
  1. Dinoprostone 10 mg insert releases Dinoprostone at 0.3 mg/hour for 12 hours
  2. Insert Pessary at Cervix
  3. Monitor Fetal Heart Tones and tocometry
    1. Start 15 to 30 minutes before insertion
    2. Continue monitoring for 15 minutes after removal
  4. Remain recumbent for 2 hours after insertion
  5. Pull Pessary out via string if hyper-stimulated
  1. Insert 25-50 mcg tablet intravaginally (100 mcg Misoprostol tablet broken into quarters)
    1. Dose of 25 mcg is preferred due to less tachysystole, Fetal Heart Rate abnormalities and neonatal complications
    2. Sublingual Misoprostol may be used instead but higher risk of complications (e.g. tachysystole)
  2. Avoid use of K-Y or other gel at time of insertion
    1. Interferes with gel dissolving
  3. Patient remains supine for 30 minutes
  4. Monitor Fetal Heart Tones and tocometry for 3 hours
  5. Repeat every 4-6 hours as needed
  6. Wait at least 3 hours before Pitocin
  7. References
    1. Vengalil (1998) Obstet Gynecol 91:774-9 [PubMed]
  • Medication
  • Newer agents (experimental)
  1. Mifepristone (Mifeprex)
    1. Antiprogesterone
  2. Relaxin Hormone
  • Adverse Effects
  1. Tachysystole
    1. Criteria: >10 contractions in 20 minutes (or >5 contractions in 10 minutes)
    2. Dinoprostone Tachysystole Incidence: 33%
    3. Misoprostol Tachysystole Incidence
      1. Intravaginal gel or tablet: 31 to 49%
      2. Oral crushed form or tablet: 16 to 22%
  2. Hyperstimulation
    1. Criteria
      1. Exaggerated uterine response (i.e. Tachysystole)
      2. Concerning Fetal Heart Rate tracing
        1. Late Decelerations
        2. Fetal Tachycardia >160 beats per minute
    2. Dinoprostone Hyperstimulation Incidence: 17%
    3. Misoprostol Hyperstimulation Incidence
      1. Intravaginal gel or tablet: 8%
      2. Oral crushed form or tablet: 1 to 2%
  3. Uterine Rupture in VBAC
    1. Risk: 2.5% in Trial of Labor after Cesarean
  4. References
    1. Crane (2001) Obstet Gynecol 97:926-31 [PubMed]
    2. Ravasia (2000) Obstet Gynecol 183:1176-9 [PubMed]
  • Complications
  • Hyperstimulation Management
  1. Consider Terbutaline SQ
  2. Dinoprostone (Cervidil): Remove
  3. Misoprostol (Cytotec): Irrigate vagina
    1. Use Normal Saline via 100 cc Syringe (no needle)
    2. Repeat several times until pill fragments recovered
  • References
  1. Adair (2000) Clin Obstet Gynecol 43:447-54 [PubMed]
  2. Crane (2001) Obstet Gynecol 97:926-31 [PubMed]
  3. Sanchez-Ramos (1997) Obstet Gynecol 89:633-4 [PubMed]
  4. Tenore (2003) Am Fam Physician 67(10):2123-8 [PubMed]
  5. Wheeler (2022) Am Fam Physician 105(2): 177-86 [PubMed]