Your baby’s umbilical cord is his lifeline, connecting him to your placenta. Any abnormality in the way it's attached to the placenta can put a pregnancy at higher risk of complications.
A velamentous cord insertion is an umbilical cord abnormality that may require monitoring during your pregnancy, but happily, with proper care, the chances that it will end up being problematic for your pregnancy or your baby are low.
What is velamentous cord insertion?
In a normal pregnancy, fetal blood vessels run via the umbilical cord directly into the middle of the mom’s placenta. A thick, white, gelatinous substance called Wharton’s jelly usually encases the umbilical cord vessels.
A velamentous cord insertion is when a fetus's umbilical cord abnormally inserts on the edge of the placenta along the chorioamniotic membranes. The fetal blood vessels also travel unprotected from the placenta until they come together and reach the protection of the umbilical cord.
This uncommon pregnancy complication occurs in about 1 percent of singleton pregnancies and in up to 15 percent of identical twin pregnancies in which a single placenta is shared by both fetuses.
It’s not entirely clear why velamentous cord insertion happens. The good news is that it rarely causes serious problems. You’ll just need more monitoring during your pregnancy and when you’re giving birth.
How is velamentous cord insertion diagnosed?
Your practitioner would likely diagnose velamentous cord insertion based on ultrasound images of the placenta and umbilical cord — usually during the second trimester. (In some cases, your doctor may detect it in first trimester scans.) A more definitive diagnosis can be made after delivery, when the placenta can be inspected by a pathologist.
When does velamentous cord insertion typically happen?
Experts don’t know the exact timeline of when the cord abnormally inserts. But it’s usually detected during a second trimester ultrasound.
More About the Placenta and Umbilical Cord
Who is most at risk of having a velamentous cord insertion?
Pregnant women have a greater chance of developing this condition if they:
- Have placenta previa (a low-lying placenta)
- Are carrying monochorionic twins (identical twins who share a single placenta)
- Have undergone IVF to get pregnant
- Are older
What pregnancy complications can occur if you have velamentous cord insertion?
Complications resulting from velamentous cord insertion are rare, but they can happen and include:
- Compression or rupture of umbilical cord blood vessels. Because the umbilical cord blood vessels closest to the placenta are unprotected in a velamentous cord insertion, the vessels are at slightly higher risk of compression or rupture. This is especially true when these vessels are located close to the cervix, as they might be if you also have vasa previa.
- Emergency C-section. There is also a chance of needing an emergency C-section if the unprotected vessels rupture during labor.
- Manual removal of the placenta after delivery. Some women with velamentous cord insertion end up needing to have their placenta manually removed after they give birth because the umbilical cord is more fragile.
- Hemorrhage during labor. Other women have an increased risk of hemorrhage during delivery of the placenta.
Close monitoring and top-notch medical care will help prevent these complications.
Can velamentous cord insertion hurt my baby?
Happily, the chances that this pregnancy complication can hurt your baby are very low. That said, velamentous cord insertion can increase the risk of preterm birth, a small-for-gestational-age baby, low Apgar score and the need for a stay in the neonatal intensive care unit (NICU) after birth.
In twin pregnancies with velamentous cord insertion, there is a slightly higher risk of intrauterine growth restriction for one or both babies.
What can you do about velamentous cord insertion?
If an ultrasound exam suggests you have a velamentous cord insertion, you may have ultrasounds more often to monitor the condition of your baby and the placenta and make sure everything is proceeding in a healthy, safe way.
Your doctor will carefully track your baby’s growth and may recommend some form of weekly testing such as a nonstress test or ultrasounds.
If everything is okay, there’s no need for your doctor to induce you early, though your practitioner likely won’t let you go longer than 40 weeks. In the absence of vasa previa or placenta previa, it’s unlikely you would need a C-section based on a diagnosis of velamentous cord insertion alone.
During labor you’ll likely need continuous monitoring with a fetal heart monitor to ensure there are no complications from the abnormal cord placement.
After delivery, it’s unlikely your practitioner will pull on the cord to help the placenta detach (as is done with normal cord insertions).
This may mean it could take longer to deliver the placenta after birth, but there’s no downside to that as long as you’re being monitored — and hopefully you’ll spend the time cuddling with your newborn.
Is there any way to prevent velamentous cord insertion?
There’s no way to prevent velamentous cord insertion — it’s something that happens for no apparent reason during fetal development.
Even in the unlikely case that this complication occurs during your pregnancy, know that it’s even rarer that the condition will cause any serious problems — you’ll just need more ultrasounds during your pregnancy and more monitoring during childbirth.
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