What is the appropriate management for a normal umbilical artery Doppler study at 38 weeks gestation?

Management of Normal Umbilical Artery Doppler at 38 Weeks Gestation

With a normal umbilical artery Doppler at 38 weeks, proceed with routine prenatal care and plan delivery at 39-40 weeks unless fetal growth restriction is present, in which case deliver at 38-39 weeks. 1, 2

Essential Clinical Context Assessment

Before finalizing your management plan, you must determine whether fetal growth restriction (FGR) is present, as this fundamentally changes the delivery timing even with normal Doppler findings:

If FGR is Present (EFW <10th percentile):

• Deliver at 38-39 weeks gestation when estimated fetal weight is between the 3rd and 10th percentile with normal umbilical artery Doppler. 1, 2
• This recommendation applies specifically to FGR with normal Doppler—the normal Doppler does not eliminate the need for earlier delivery when growth restriction exists. 1

If No FGR (Normal Growth):

• Continue routine prenatal care with delivery planning at 39-40 weeks. 3
• The normal Doppler at 38 weeks is reassuring and supports expectant management to full term. 3

Critical Additional Assessments Required

Do not rely solely on the Doppler result. Complete the following evaluations to ensure safe expectant management:

• Amniotic fluid volume assessment using either amniotic fluid index (AFI) or maximum vertical pocket measurement—oligohydramnios (AFI <5 cm) at 38 weeks mandates immediate delivery regardless of normal Doppler. 3, 4
• Estimated fetal weight to definitively rule out FGR, as even mild growth restriction changes your delivery timing. 3
• Fetal surveillance with cardiotocography to confirm reassuring fetal status. 2

Surveillance Protocol Until Delivery

For pregnancies with FGR and normal Doppler awaiting delivery at 38-39 weeks:

• Serial umbilical artery Doppler assessment every 2 weeks to monitor for deterioration. 1, 2
• Weekly cardiotocography testing after viability for ongoing fetal well-being assessment. 1
• If Doppler deteriorates to show decreased diastolic flow, deliver immediately at 37+ weeks. 1, 2

Common Pitfalls to Avoid

• Do not delay delivery beyond 39 weeks if FGR is present, even with normal Doppler—the growth restriction itself increases perinatal risk. 1, 4
• Do not ignore oligohydramnios at term; severe oligohydramnios (AFI ≤3 cm) combined with any concern for FGR is an independent indication for delivery at 38 weeks. 4
• Do not assume normal Doppler excludes all risk—FGR with normal Doppler still carries increased risk of intrapartum complications requiring close monitoring during labor. 2, 5
• Do not use middle cerebral artery, ductus venosus, or uterine artery Doppler for routine clinical management decisions, as these are not recommended for standard FGR management. 1, 2

Mode of Delivery Considerations

With normal umbilical artery Doppler at 38 weeks:

• Induction of labor is reasonable if FGR is present and you are proceeding with delivery at 38-39 weeks. 4
• Continuous fetal monitoring during labor is mandatory if FGR is present, as these fetuses remain at higher risk for intrapartum hypoxia despite normal Doppler. 4
• Cesarean delivery is not routinely indicated based solely on normal Doppler findings—reserve cesarean for standard obstetric indications. 1, 2