What is the next step in management for a 37-week pregnant patient with a fundal height corresponding to 35 weeks and absent end-diastolic flow on umbilical artery Doppler (ultrasound)?

Management of Fetal Growth Restriction with Absent End-Diastolic Flow at 37 Weeks

Immediate delivery by cesarean section (Option B) is the appropriate next step for this 37-week pregnancy with fetal growth restriction and absent end-diastolic flow on umbilical artery Doppler. 1, 2

Why Immediate Cesarean Delivery is Mandatory

The patient is already past the recommended delivery threshold, as multiple guidelines recommend delivery by 33-34 weeks for absent end-diastolic flow, making this a high-risk scenario requiring urgent intervention. 1, 2

• Absent end-diastolic flow indicates severe placental insufficiency with obliteration of approximately 70% of placental tertiary villi arteries, representing extreme fetal compromise 2
• The fetus cannot tolerate the stress of labor contractions given this degree of placental dysfunction, with 75-95% of growth-restricted pregnancies with absent end-diastolic flow requiring emergency cesarean delivery for intrapartum heart rate abnormalities 1
• International guidelines uniformly recommend delivery by 37 weeks when abnormal umbilical artery Doppler is present, and this patient has already reached that threshold 3

Why Induction of Labor is Contraindicated

• Cesarean delivery should be strongly considered (rather than induction) for fetal growth restriction complicated by absent end-diastolic flow, as these fetuses cannot tolerate uterine contractions 2, 4
• If end-diastolic flow is present (which it is not in this case), induction with continuous fetal monitoring could be considered, but absent flow mandates cesarean delivery 3

Why Delayed Delivery is Inappropriate

• Delaying delivery by one week (Option C) is dangerous, as absent end-diastolic flow is associated with perinatal mortality rates of 60-63% when delivery is delayed 5, 6
• The Society for Maternal-Fetal Medicine recommends delivery at 33-34 weeks for absent end-diastolic flow; at 37 weeks, this patient is already 3-4 weeks beyond the recommended delivery window 1, 2
• Research demonstrates that absent end-diastolic flow always precedes fetal distress, and immediate delivery is indicated once this finding appears 7

Critical Pre-Delivery Actions

• Coordinate with neonatology for optimal resuscitation planning, as these infants are at high risk for respiratory distress syndrome, necrotizing enterocolitis, and intraventricular hemorrhage 2, 8
• Antenatal corticosteroids are not indicated at 37 weeks (only recommended up to 36+6 weeks), so this should not delay delivery 3, 1
• Magnesium sulfate for neuroprotection is not indicated, as this is only recommended before 32 weeks gestation 1, 4

Essential Post-Delivery Management

• Obtain cord arterial and venous pH at delivery to assess the degree of fetal compromise 1, 4
• Send the placenta for histopathologic examination to guide future pregnancy management 1, 4

Common Pitfalls to Avoid

• Do not attempt labor induction or augmentation with absent end-diastolic flow, as the severe placental compromise makes the fetus unable to tolerate contractions 4
• Do not confuse absent end-diastolic flow with reversed end-diastolic flow (which is even more severe and has mortality rates exceeding 60%) 7, 5
• Do not delay delivery for additional testing or surveillance at this gestational age, as the patient is already term and the risk of intrauterine fetal demise is substantial 2, 6