title: The added predictive value of biphasic events in ST analysis of the fetal electrocardiogram for intrapartum fetal monitoring.
abstract: OBJECTIVE
  To study the predictive value of biphasic ST-events for interventions for suspected fetal distress and adverse neonatal outcome, when using ST-analysis of the fetal electrocardiogram (FECG) for intrapartum fetal monitoring.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Three academic hospitals in Sweden.
  
  
  METHODS
  Women in labor with a high-risk singleton fetus in cephalic position beyond 36 weeks of gestation.
  
  
  METHODS
  In women in labor who were monitored with conventional cardiotocography, ST-waveform analysis was recorded and concealed. Traces with biphasic ST-events of the FECG (index) were compared with traces without biphasic events of the FECG. The ability of biphasic events to predict interventions for suspected fetal distress and adverse outcome was assessed using univariable and multivariable logistic regression analyses.
  
  
  METHODS
  Interventions for suspected fetal distress and adverse outcome (defined as presence of metabolic acidosis (i.e. umbilical cord pH <7.05 and base deficit in extracellular fluid >12 mmol), umbilical cord pH <7.00, 5-min Apgar score <7, admittance to neonatal intensive care unit or perinatal death).
  
  
  RESULTS
  Although the presence of biphasic events of the FECG was associated with more interventions for fetal distress and an increased risk of adverse outcome compared with cases with no biphasic events, the presence of significant (i.e. intervention advised according to cardiotocography interpretation) biphasic events showed no independent association with interventions for fetal distress [odds ratio (OR) 1.71, 95% confidence interval (CI) 0.65-4.50] or adverse outcome (OR 1.96, 95% CI 0.74-5.24).
  
  
  CONCLUSIONS
  The presence of significant biphasic events did not discriminate in the prediction of interventions for fetal distress or adverse outcome. Therefore, biphasic events in relation to ST-analysis monitoring during birth should be omitted if future studies confirm our findings.
authors.affiliation: Department of Obstetrics and Gynecology, Zuwe Hofpoort Hospital, Woerden, the Netherlands.
authors.forename: Jeroen H
authors.initials: JH
authors.lastname: Becker
authors.forename: Anniek
authors.initials: A
authors.lastname: Krikhaar
authors.forename: Ewoud
authors.initials: E
authors.lastname: Schuit
authors.forename: Annika
authors.initials: A
authors.lastname: Mårtendal
authors.forename: Karel
authors.initials: K
authors.lastname: Maršál
authors.forename: Anneke
authors.initials: A
authors.lastname: Kwee
authors.forename: Gerard H A
authors.initials: GH
authors.lastname: Visser
authors.forename: Isis
authors.initials: I
authors.lastname: Amer-Wåhlin
mesh_terms: D019540:Area Under Curve; D015148:Cardiotocography; D004562:Electrocardiography; D005260:Female; D005316:Fetal Distress / Q000175:diagnosis* / Q000503:physiopathology; D005318:Fetal Heart / Q000503:physiopathology; D005323:Fetal Monitoring / Q000379:methods*; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome
keywords: Biphasic events; ST-analysis; fetal electrocardiogram; neonatal outcome