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Fetal Fibronectin

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Fetal Fibronectin

  • Indication
  1. Preterm Labor Evaluation
  • Mechanism
  1. Extracellular glycoprotein glues cell together
    1. Found between many cell types
    2. Binds placenta to Decidua
  2. Normally present in vagina in early pregnancy
    1. Not normally found in vagina after 20 weeks gestation
  3. Presence >20 weeks gestation suggests Preterm Labor
  • Contraindications
  • False positive fibronectin risks
  1. Vaginal exam within prior 24 hours
  2. Sexual intercourse within prior 48 hours
  3. Moderate Vaginal Bleeding
  • Interpretation
  1. Negative fibronectin is reassuring for 2 weeks
    1. If no cervical change, <10% preterm delivery risk
    2. Iams (2002) N Engl J Med 346:250-5 [PubMed]
  2. Positive fibronectin
    1. Once positive, no longer useful for monitoring
    2. Low Specificity for preterm delivery
  • Efficacy
  1. Does not affect Gestational age at delivery
  2. Does not affect rate of inpatient admissions
  3. Does not affect frequency of medical interventions
  4. Lowe (2004) Am J Obstet Gynecol 190:358-62 [PubMed]