Is admission under observation and possible termination of pregnancy warranted for a 34-week gestation with abnormal fetal surveillance findings, including decreased beat-to-beat variation on cardiotocography (CTG) and abnormal Doppler indices?

Assessment of Ultrasound Report and Management Plan for 34-Week Gestation with Abnormal Fetal Surveillance

Critical Analysis of the Reported Doppler Values

The reported umbilical artery Doppler indices (RI 0.69, S/D ratio 3.2) are actually NORMAL for 34 weeks gestation, and the management plan describing these as "abnormal" and "increased" is incorrect. 1

• Normal umbilical artery S/D ratio at 34 weeks is typically less than 3.0, but values up to 3.2 remain within acceptable limits for this gestational age 1
• The RI of 0.69 falls within the normal range for third trimester pregnancies 1
• The report's assertion that "normal at this age less than 3" for S/D ratio is overly stringent and does not align with established reference ranges 1

Primary Concern: Decreased Beat-to-Beat Variability on CTG

The admission is justified based on the decreased beat-to-beat variability on cardiotocography that failed to improve with resuscitative measures, NOT based on the Doppler findings. 2

Appropriate Management of Category 2 CTG Pattern

• Decreased beat-to-beat variability represents a Category 2 (indeterminate) fetal heart rate pattern requiring increased surveillance 2
• The interventions attempted (IV fluids, left lateral position, oxygen) were appropriate initial resuscitative measures 2
• Admission for observation with serial fetal surveillance is warranted when Category 2 patterns persist despite resuscitative efforts 2

Recommended Surveillance Protocol

• For Category 2 CTG at 34 weeks with normal umbilical artery Doppler, increase monitoring frequency to at least twice weekly 2, 3
• Continue daily cardiotocography monitoring during inpatient observation 2
• Repeat biophysical profile assessment, as the BPP is more specific than sensitive for identifying fetal compromise 1
• Consider additional Doppler evaluation of middle cerebral artery and ductus venosus to assess for cerebral redistribution or venous compromise 1

Delivery Timing Considerations

At 34 weeks with normal umbilical artery Doppler and persistent Category 2 CTG, expectant management with intensive surveillance is appropriate rather than immediate delivery. 2, 3

Gestational Age-Specific Guidelines

• For fetal growth restriction with normal umbilical artery Doppler (which this case appears to have based on estimated fetal weight of 2214g at 34 weeks), delivery is recommended at 38-39 weeks 3, 4
• Immediate delivery at 34 weeks would only be indicated if there were absent or reversed end-diastolic flow in the umbilical artery, which is NOT present in this case 3, 4
• If CTG deteriorates to Category 3 (abnormal) or if ductus venosus shows reversed A-wave flow, earlier delivery would be warranted 1

Additional Surveillance Recommendations

The following assessments should be performed during the observation period:

• Serial umbilical artery Doppler every 1-2 weeks to monitor for deterioration 1
• Middle cerebral artery Doppler to evaluate for brain-sparing physiology, which would indicate worsening placental insufficiency 1
• Ductus venosus Doppler if CTG abnormalities persist, as reversed A-wave flow is associated with neonatal demise and would prompt delivery 1, 5
• Daily biophysical profile scoring during inpatient observation 1

Corrected Clinical Impression

The ultrasound findings are appropriate and technically adequate, but the interpretation of Doppler indices as "abnormal" is incorrect. The primary indication for admission is the non-reassuring CTG pattern (decreased variability unresponsive to resuscitation), not abnormal Doppler studies. 2

Key Points for Management

• Admission for observation is justified based on CTG findings alone 2
• The plan should emphasize intensive fetal surveillance with daily CTG and serial Doppler studies 2, 3
• "Possible termination of pregnancy" at 34 weeks is premature unless there is clear evidence of fetal decompensation (Category 3 CTG, reversed ductus venosus flow, or biophysical profile ≤4) 1, 2
• Antenatal corticosteroids should be administered given the possibility of delivery before 37 weeks 2

Common Pitfalls to Avoid

• Do not misinterpret borderline-normal Doppler values as pathological, as this leads to unnecessary interventions and iatrogenic prematurity 1
• Avoid relying solely on CTG without integrating comprehensive Doppler assessment of multiple vessels 1
• Do not proceed to immediate delivery at 34 weeks based on Category 2 CTG alone without evidence of progressive deterioration 1, 2
• Ensure repeat CTG assessment occurs within 24 hours, as fetal status can deteriorate rapidly in the setting of placental insufficiency 2, 5