What is the recommended management for a pregnancy with velamentous cord insertion?

Management of Velamentous Cord Insertion in Pregnancy

Pregnancies with velamentous cord insertion require increased surveillance with ultrasound every 2-3 weeks beginning at 16 weeks gestation due to higher risks of adverse perinatal outcomes including fetal growth restriction, preterm delivery, and stillbirth. 1

Understanding Velamentous Cord Insertion

Velamentous cord insertion is an abnormal placental cord insertion where:

• The umbilical vessels branch before reaching the placenta
• Blood vessels travel unprotected through the membranes before connecting to the placental surface
• Occurs in approximately 1% of singleton pregnancies but is more common in multiple gestations (up to 22% in monochorionic twins) 1

Risk Factors

• Multiple gestations (9.2x increased risk) 2
• Infertility treatments (4.3x increased risk) 2
• Chronic hypertension (2.2x increased risk) 2

Recommended Management Protocol

First Trimester

• Confirm diagnosis with transabdominal and transvaginal ultrasound with color Doppler 1, 3
• Document the location of cord insertion for each fetus 1
• If in a twin pregnancy, determine chorionicity (especially important as velamentous insertion is more common in monochorionic pregnancies) 1

Second Trimester

• Detailed anatomy scan at 18-22 weeks 1
• Screen for associated anomalies, particularly in multiple gestations
• Fetal echocardiography is recommended, especially in monochorionic twins, due to increased risk of cardiac anomalies 1
• Assess for vasa previa (when velamentous vessels cross the internal cervical os) 1

Ongoing Surveillance

• Serial ultrasound evaluations every 2-3 weeks starting at 16 weeks 1
• Monitor for:
  • Fetal growth restriction (1.93x increased risk) 4
  • Amniotic fluid abnormalities (polyhydramnios is 2.3x more common) 2
  • Umbilical artery Doppler abnormalities in cases of growth discrepancy 1
  • In twin pregnancies: signs of twin-twin transfusion syndrome (TTTS) 1

Special Considerations for Multiple Gestations

• Velamentous cord insertion in one or both twins increases risk of TTTS by 27% compared to 7% in twins with normal cord insertions 1
• Increases risk of discordant growth between twins 1
• In monochorionic twins, consider weekly surveillance if velamentous insertion is identified 1

Delivery Planning

• Mode of delivery:

  • Consider cesarean delivery, especially with vasa previa or other complications (emergency cesarean risk is 2.03x higher) 4
  • Elective cesarean should be considered to avoid cord compression or vessel rupture during labor 5

• Timing of delivery:

  • For uncomplicated cases: standard timing based on other obstetric factors
  • For cases with growth restriction or other complications: individualized timing based on severity
  • For monochorionic twins with velamentous insertion: earlier delivery may be warranted due to increased complications 1, 4

Associated Complications and Risks

Velamentous cord insertion significantly increases the risk of:

• Stillbirth (4.12x increased risk) 4
• Small-for-gestational-age neonates (1.93x increased risk) 4
• Preterm delivery (2.14x increased risk) 4
• Placental abruption (2.94x increased risk) 4
• Low Apgar scores at 5 minutes (1.97x increased risk) 4
• NICU admission (1.63x increased risk) 4

Clinical Pitfalls to Avoid

• Failure to diagnose: Systematic assessment of cord insertion should be part of routine obstetric ultrasound 3
• Inadequate imaging: Color Doppler significantly improves detection compared to gray-scale ultrasound alone 3
• Missing associated vasa previa: Always evaluate for vessels crossing the internal cervical os 1
• Underestimating risks: Even without vasa previa, velamentous insertion carries significant risks including 9.42x increased risk of stillbirth 4
• Insufficient monitoring: Standard antepartum testing alone (NST) has been shown to be ineffective (only 5% of cases show abnormal NST results) 6

By implementing this surveillance protocol, the risks associated with velamentous cord insertion can be significantly mitigated, improving perinatal outcomes.