What is the management and treatment for a pregnant woman with fetal umbilical vein varix?

Management of Fetal Umbilical Vein Varix

For pregnancies with fetal umbilical vein varix, perform close fetal surveillance with serial ultrasounds, conduct a thorough anatomic survey including fetal echocardiography to rule out associated anomalies, and plan for early delivery at 34 weeks' gestation or sooner if fetal distress develops, given the unpredictable course and high risk of adverse outcomes including intrauterine fetal demise. 1, 2

Initial Diagnostic Workup

When umbilical vein varix is identified, immediate comprehensive evaluation is essential:

• Detailed anatomic survey should be performed to identify associated structural anomalies, which occur in approximately 35% of cases 3
• Fetal echocardiography is mandatory, as cardiac anomalies are among the most common associated findings 3
• Karyotyping should be discussed if other anomalies are present, as chromosomal abnormalities can occur (including reported cases of triploidy) 3
• Rule out isoimmunization through maternal antibody screening, as Kell isoimmunization has been reported in association with umbilical vein varix 3

The distinction between intra-abdominal and extra-abdominal varix matters clinically, as extra-abdominal varices carry particularly high risk with 50% fetal heartbeat abnormalities, 14% fetal death rate, and 86% incidence of intra-umbilical cord thrombosis 4

Surveillance Protocol

Weekly umbilical artery Doppler should be performed if fetal growth restriction develops, as recommended by the American College of Obstetricians and Gynecologists 5

Additional monitoring should include:

• Serial ultrasound examinations to monitor varix size, detect thrombosis formation, and assess fetal growth 1, 2
• Middle cerebral artery peak systolic velocity assessment to screen for fetal anemia, particularly with extra-abdominal varices where hemolytic anemia from turbulent flow can occur 4
• Cardiotocography for fetal well-being assessment, especially in the third trimester 2
• Assessment for fetal hydrops, cardiomegaly, and decreased fetal movements as warning signs of hemodynamic compromise 4

Thrombosis Prevention Consideration

One small case series reported using low-dose aspirin prophylaxis until 35 weeks' gestation in four consecutive cases, with no thrombosis development and good neonatal outcomes 6. However, this represents limited evidence from a single center without controlled comparison, and no formal guidelines exist regarding thromboprophylaxis for this condition.

Timing and Mode of Delivery

Delivery should be planned at 34 weeks' gestation when lung maturity is accomplished, or earlier if any signs of fetal distress appear 1, 2

The rationale for early delivery includes:

• Unpredictable natural history with documented cases of intrauterine fetal demise occurring despite close monitoring 2
• High fetal mortality rate associated with this condition, particularly when complications develop 2
• Risk of sudden thrombosis leading to acute fetal compromise 1, 2

Earlier delivery is indicated if:

• Non-reassuring fetal status develops 4
• Signs of fetal anemia appear (elevated MCA-PSV >1.5 MoM) 4
• Fetal growth restriction with abnormal Doppler findings develops 5
• Evidence of thrombosis formation within the varix 4

Critical Pitfalls to Avoid

• Do not assume isolated varix is benign: Even when appearing isolated initially, 35% have associated anomalies and adverse outcomes can occur despite normal surveillance 3, 2
• Do not rely solely on standard fetal surveillance: The course is unpredictable and sudden deterioration can occur between monitoring sessions 2
• Do not overlook extra-abdominal location: Extra-abdominal varices carry particularly high risk and warrant even closer surveillance 4
• Do not delay delivery beyond 34-35 weeks in the absence of complications, as the risk-benefit ratio favors earlier delivery given the potential for sudden adverse events 1, 2

Postnatal Considerations

Pediatric providers should be notified at delivery about the prenatal diagnosis, as neonatal examination and follow-up are important to identify any previously undetected anomalies 3