BACKGROUND AND PURPOSE:

• The clinical utility of EFM has been challenged, but there is evidence that it may reduce neonatal seizures
• Farquhar et al. (JAMA Netw Open., 2020) explored whether experienced clinicians could detect and develop action plans for abnormal FH tracings that were recorded during the next to last hour before birth of infants who were diagnosed with moderate to severe neonatal encephalopathy (NE)

METHODS:

• Case-control study (New Zealand)
• Participants
  • Practicing, experienced obstetricians and midwives
  • Completed a fetal surveillance education program within 2 years
• Neonatal encephalopathy (NE)
  • Defined as “disordered neonatal brain function within the first week of life in term infants”
• Study design
  • Participants were masked to the perinatal outcome | Provided with clinical details and 1 hour of FH tracing from 2 hours before birth
  • Case group: Tracings from neonates with NE and evidence of birth hypoxia and without an acute perinatal event
  • Control group: Tracings from neonates without NE or birth hypoxia
  • Clinicians recommended a plan based on their assessment
  • A year later, clinician assessors were asked to relook at the tracings
• Statistical analysis
  • 80% power at a significance level of .05 to detect a difference in rates of immediate response for abnormal tracing | Assumption based on difference in rates (controls vs cases): 1% and 15%, 5% and 25%, and 10% and 35%
• Primary outcomes
  • Sensitivity for detection of hypoxia: Proportion of cases where tracing was read as abnormal
  • Sensitivity for appropriate management of hypoxia: Proportion of cases where assessors developed an immediate plan (e.g. immediate delivery by cesarean or instrumental delivery) dependent on clinical findings
  • Specificity: Proportion of controls where assessors rated a tracing as normal and made no plan for immediate action

RESULTS:

• 10 clinicians participated
• Infant characteristics
  • Cases: 35 infants | Mean (SD) gestational age, 40 (1.4) weeks | 45.7% cesarean
  • Controls: 105 infants | Mean (SD) gestational age, 39.4 (1.2) weeks | 21% cesarean
• Detection rate for hypoxia across all assessors: Mean (range) was
  • Sensitivity: 75% (63% to 91%)
  • Specificity: 67% (53% to 77%)
• Recommendation for appropriate management across all assessors: Mean (range) was
  • Sensitivity: 41% (23% to 57%)
  • Specificity: 87% (65% to 99%)
• A sensitivity analysis was performed that only included assessors with 80% or more interassessor agreement
  • Mean (range) sensitivity for detection: 76% (63% to 91%)
  • Sensitivity for action plan: 36% (25% to 49%)
  • Specificity for detection: 71% (53% to 77%)
  • Specificity for action plan: 93% (88% to 99%)
• Intraassessor agreement (same tracings 1 year later)
  • Identifying abnormal tracings: 63% to 93%
  • Planning immediate action: 70% to 93%

CONCLUSION:

• In this study, clinicians used a tool based on NICE guidelines and elements of the RANZCOG guidance | Compared to ACOG, NICE is more sensitive but ACOG is more specific
• The authors recognize important study limitations, including the inability to definitively rule out an antepartum cause for NE, although blood gasses provide evidence for case inclusion
• Highly experienced clinicians could detect 3 out of 4 infants who would subsequently be diagnosed with NE
• Clinicians recommended action to expedite delivery for >40% of infants with NE
• “Most assessors only agreed with themselves 70% to 80% of the time”
• The authors conclude that
  • EFM alone does not identify all infants at risk of NE
  • Further investment is needed into clinician education and alternative approaches to fetal surveillance in labor
• The authors state that EFM is “embedded” into obstetrical care and

If this is as good as it gets, then we will continue to see rising intervention rates in women with no fetal hypoxia while continuing to fail some infants at risk

Learn More – Primary Sources:

Clinician Identification of Birth Asphyxia Using Intrapartum Cardiotocography Among Neonates With and Without Encephalopathy in New Zealand

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