MFM Patient Consultation

Understanding Your
Ultrasound Findings

Umbilical Vein Varix & Persistent Right Umbilical Vein

Uncommon Finding Often Reassuring Monitoring-Based Care

Foundation

The Umbilical Vein

A single vein in the umbilical cord carries oxygen-rich blood from the placenta to your baby's liver and heart.

Condition 1

Umbilical Vein Varix (UVV)

A focal widening or ballooning of the umbilical vein — most often in the portion inside the baby's abdomen.

<1%

of all pregnancies

≥9 mm

diagnostic diameter threshold

Condition 2

Persistent Right Umbilical Vein (PRUV)

Normally, the right umbilical vein closes by week 7. In PRUV, the right vein remains open while the left vein disappears — a variation in vessel development.

0.1–0.5%

prevalence in pregnancy

73–98%

good outcome when isolated

At a Glance

UVV vs. PRUV — Key Differences

Feature	Umbilical Vein Varix (UVV)	Persistent Right Umbilical Vein (PRUV)
What it is	Focal ballooning of the vein	Wrong vein persists; right instead of left
How it is found	Dilated segment on ultrasound (≥9 mm)	Vein curves toward the stomach on scan
Prevalence	<1% of pregnancies	0.1–0.5% of pregnancies
Isolated prognosis	Generally favorable; no increased IUFD risk before 39 wks	Excellent; 73–98% good outcome
Key concern	Growth restriction; rare thrombosis	Cardiac, GI, or renal anomalies if non-isolated
Monitoring focus	Serial growth scans + Doppler	Detailed anatomy scan + fetal echo

Prognosis

Isolated vs. Non-Isolated

The single most important question: Is this the only finding?

✓ Isolated Finding

No other structural abnormalities detected. Prognosis is generally very good. Most babies are born healthy with appropriate monitoring.

⚠ Non-Isolated Finding

Other anomalies are present in 25–35% of UVV cases and a subset of PRUV cases. Additional evaluation and specialist input are required.

💡 Your care team will determine whether your finding is isolated through a detailed anatomy scan and fetal echocardiogram.

What Happens Next

Your Evaluation Plan

A structured evaluation ensures no associated findings are missed.

1

Detailed Anatomy Scan

Level II ultrasound — all organs reviewed

2

Fetal Echocardiogram

Dedicated heart study

3

Genetic Counseling

If additional findings are present

4

Serial Monitoring

Growth scans + Doppler every 4 weeks

Monitoring — UVV

Watching the Varix

For umbilical vein varix, serial assessments track key parameters throughout pregnancy.

Fetal Growth Scans

Varix Size Measurement

Doppler Blood Flow

Thrombosis Screening

⚠️ Important: If you notice a significant decrease in fetal movement, contact your care team immediately for evaluation.

Monitoring — PRUV

Monitoring a Persistent Right Umbilical Vein

If PRUV is the only finding, monitoring is straightforward and reassuring.

Detailed anatomy scan to confirm no associated structural anomalies
Fetal echocardiogram — cardiac defects are the most common associated finding
Standard prenatal care schedule if no other issues are identified
Multidisciplinary team involvement if additional anomalies are detected

✅ Isolated PRUV carries an excellent prognosis. The majority of affected babies are born healthy and require no special postnatal treatment.

Delivery

Planning Your Delivery

When the finding is isolated and monitoring is reassuring, delivery planning follows a standard approach.

Timing

Delivery is typically planned around 37–39 weeks of gestation for isolated UVV. Earlier delivery is only considered if growth restriction, thrombosis, or fetal distress is detected.

Mode of Delivery

Vaginal delivery is generally safe unless there is another obstetric indication for cesarean section. Your MFM team will coordinate with your delivery hospital.

⚠️ Turbulent flow or thrombus within the varix is a critical finding that may require urgent delivery. This will be monitored closely at every scan.

Your Voice Matters

Questions to Ask Your Doctor

Is this finding isolated, or were other abnormalities seen?
How often will I need ultrasounds, and what are we watching for?
Do I need a fetal echocardiogram, and when?
What signs or symptoms should prompt me to call right away?
Where should I plan to deliver, and will my baby need special care after birth?
Are there any activity restrictions I should follow?

Partnership in Care

We Are Your Partners

These are uncommon findings, but when isolated, most babies do very well. Our team will monitor your baby closely, answer every question, and support you at every step.

Most

isolated cases have
healthy outcomes

Serial

monitoring keeps
your baby safe

Always

ask questions —
no concern is too small

Information consistent with ACOG, SMFM, and current evidence-based guidelines.
This material supports — and does not replace — a conversation with your physician.

Understanding Your Ultrasound Findings