Velamentous Umbilical Cord Insertion: Patient Education
Velamentous cord insertion is a condition where the umbilical cord attaches to the placental membranes instead of directly into the placental mass, leaving blood vessels unprotected as they travel through the membranes before reaching the placenta. 1
What Is Velamentous Cord Insertion?
In a normal pregnancy, the umbilical cord inserts directly into the center of the placenta. With velamentous cord insertion:
- The umbilical cord attaches to the fetal membranes (the amniotic sac) rather than the placental mass
- Blood vessels from the cord must travel unprotected through the membranes before reaching the placenta
- These exposed vessels are vulnerable to compression, rupture, or injury during pregnancy and labor
How Common Is It?
- Occurs in approximately 1% of singleton pregnancies
- Much more common in twin pregnancies, especially monochorionic twins (sharing one placenta), where it can occur in up to 22% of cases 1, 2
- More frequently seen in pregnancies conceived through fertility treatments 3
How Is It Diagnosed?
Velamentous cord insertion is typically diagnosed during pregnancy using:
- Ultrasound with color Doppler imaging, which significantly improves detection compared to regular ultrasound 1
- The condition can be identified during routine second-trimester ultrasound examinations 2
- Special attention is given to checking for vasa previa (a dangerous condition where exposed blood vessels cross over the cervical opening) 1
Associated Risks and Complications
Velamentous cord insertion is associated with several potential complications:
- Increased risk of intrauterine growth restriction (baby not growing properly)
- Higher chance of preterm birth
- Increased risk of placental abruption (placenta separating early)
- Polyhydramnios (excess amniotic fluid)
- Higher rates of cesarean delivery
- Lower Apgar scores (assessment of baby's condition at birth)
- In twin pregnancies, it increases the risk of twin-twin transfusion syndrome 1, 3
Management During Pregnancy
If velamentous cord insertion is diagnosed:
- Increased monitoring with ultrasound every 2-3 weeks starting at 16 weeks of pregnancy 1
- Close monitoring of fetal growth and amniotic fluid levels
- For twin pregnancies, especially monochorionic twins, more intensive monitoring may be needed
- Fetal echocardiography (detailed ultrasound of the baby's heart) may be recommended, especially in twin pregnancies 1
Delivery Considerations
- Vaginal delivery is often possible when vasa previa has been ruled out 1
- Continuous fetal monitoring during labor is essential
- Artificial rupture of membranes (breaking the water) may be avoided when possible
- Cesarean delivery may be recommended in certain cases, particularly if vasa previa is present 1, 3
Important Warning Signs
During pregnancy, contact your healthcare provider immediately if you experience:
- Vaginal bleeding
- Decreased fetal movement
- Premature contractions
Early detection and appropriate management of velamentous cord insertion significantly reduce the risk of complications and help ensure a safer pregnancy and delivery.