Marginal Cord Insertion

What is marginal cord insertion?

Marginal cord insertion is a type of abnormal umbilical cord attachment during pregnancy. The umbilical cord is the lifeline that connects a fetus to its mother (birthing parent) via a shared organ called the placenta. Nutrients and oxygen from the placenta travel through the umbilical cord and to the fetus, allowing it to grow and develop.

With a normal cord insertion, the umbilical cord inserts in the center of the placenta. The center is the most secure place of attachment. Normal attachment supports the seamless flow of nutrients from parent to the placenta to and fetus.

With a marginal cord insertion, the umbilical cord attaches at the edge of the placenta (about 20 millimeters away from the margin) instead of in the center, where it’s less secure. In some — but not all — cases, this type of attachment may slow the flow of nutrients from the placenta to the fetus, causing the fetus to develop more slowly — a condition called IUGR (intrauterine growth restriction). This could also lead to a decelerated fetal heart rate during labor. But, it’s important to note that most pregnancies with marginal cord insertion will have a normal outcome.

What qualifies as a marginal insertion of the umbilical cord?

Marginal cord insertion occurs when the umbilical cord is within two centimeters or less from the edge of the placenta. The umbilical cord is still attached, just not in the center.

How common is marginal cord insertion?

Marginal cord insertion is more common in multiple births (births involving twins, triplets, etc.) than in pregnancies involving one baby. Occurrence ranges from 2% to 25% of pregnancies, with singleton pregnancies (one baby) being on the low end and multiple births (more than one baby) on the high end of this range.

What are the symptoms of marginal placental cord insertion?

You likely won’t experience symptoms. Instead, your healthcare provider will notice atypical umbilical cord attachment during a routine pregnancy ultrasound.

What causes marginal cord insertion?

Researchers aren’t sure what causes marginal cord insertion. Still, certain factors may increase the likelihood of an atypical umbilical cord attachment. Marginal cord insertion is most common in pregnancies involving more than one baby (twins, triplets). Other factors may include:

• Drug abuse during pregnancy.
• Having a chronic disease, such as diabetes.
• Advanced maternal age (being 35 or older).
• Nulliparity (this is your first time giving birth).
• Using an intrauterine device (IUD) before pregnancy.
• Using artificial reproductive technology (ART) to get pregnant.

Having one or more of these factors apply to you doesn’t mean you’ll experience an abnormal cord insertion. For instance, many people who use ART have normal cord insertions. Most importantly, many people with irregular cord insertions have healthy pregnancies.

When is marginal cord insertion usually diagnosed?

Most abnormal cord insertions are detected during the second trimester of pregnancy (weeks 14 to 27). Still, it may be difficult for your healthcare provider to pinpoint precisely where the umbilical cord has attached to the placenta.

Your provider may use the doppler feature during an ultrasound to visualize the blood flow between the placenta and the fetus. This information can be helpful when trying to identify the umbilical cord insertion point.

What is the treatment for marginal cord insertion?

No treatments exist that can correct a marginal cord insertion. Instead, your healthcare provider will closely monitor your pregnancy to prevent complications.

The provider will monitor the growth of the baby, and look for other potential risks. At times a c-section may be recommended.

Close monitoring can reduce your risk of these outcomes.

Can I prevent a marginal cord insertion?

No. You can’t prevent a marginal cord insertion. Still, you can work closely with your healthcare provider to monitor your pregnancy and take actions to increase your chances of successful delivery and a healthy baby.

Does marginal cord insertion correct itself?

It’s possible. Often, marginal cord insertion doesn’t pose risks to the pregnancy or prevent the fetus from getting enough nutrients. If this is the case, you shouldn’t worry about how the cord is inserted. Instead, trust your provider to monitor the fetus’s development so that you can focus on maintaining your health during pregnancy.

Is marginal cord insertion considered high risk?

Any type of atypical umbilical cord attachment can pose pregnancy risks, but don’t assume the worst if you learn of a marginal cord insertion. Most diagnosed marginal cord insertions result in healthy pregnancies.

Your healthcare provider can discuss any concerns after reviewing your medical history and your ultrasound. The biggest concern is often intrauterine growth restriction (IUGR). With IUGR, the fetus develops more slowly than usual. You may be at risk of IUGR if the fetus isn’t getting enough nutrients from the placenta. IUGR increases the risk of a newborn with:

• Low birth weight: A baby with low birth weight is less than 5 lbs. 8 oz.
• Low Apgar score: The Apgar test checks your baby’s health immediately after birth. A low Apgar score may mean that your newborn may have problems with their heart or lungs. Babies with low Apgar scores require additional care after they’re born.
• Increased chances of a NICU stay: Your baby may need to stay in the neonatal intensive care unit (NICU) to receive additional nurturing until they are healthy enough to be moved to the nursery.

Your provider may recommend a c-section if they're concerned about risks to you or your baby.

How often does marginal cord insertion turn into velamentous cord insertion?

A marginal cord insertion can become velamentous, especially during the third trimester (weeks 29 to 40), but this is rare. With velamentous cord insertion, the cord doesn’t attach to the placenta. Instead, it attaches to membranes outside of the placenta. Velamentous cord insertion is less common and more concerning than marginal cord insertion. It occurs in approximately 1% of pregnancies.

Your provider can monitor umbilical cord attachment to ensure the best outcomes with marginal and velamentous cord insertion.

Should I worry about marginal cord insertion?

You shouldn’t worry. The majority of people with marginal cord insertions have healthy newborns. If the fetus is receiving the nutrients it needs to develop, a marginal cord insertion may not impact your pregnancy at all.

Speak to your provider about any concerns you may have. Many factors shape the risks involved with any pregnancy. Abnormal umbilical cord attachment may pose risks or it may not. Your provider can provide an honest assessment to help guide your pregnancy.

What questions should I ask my doctor?

• How often will I need ultrasounds to monitor my pregnancy?
• Should I consider other tests?
• What is the likelihood that marginal cord insertion will impact my pregnancy?
• Are there additional tests that will be needed to check my baby’s development?
• How can I adjust my diet, exercise and sexual activity to have the healthiest pregnancy possible?
• How much sleep should I be getting each night?
• How much rest should I be getting each day?

A note from Cleveland Clinic

Learning of a marginal cord insertion can be scary, but don’t let this diagnosis add unnecessary stress to your pregnancy. A marginal cord insertion may require additional monitoring or care. It’s also possible that a marginal cord insertion may not impact your pregnancy at all. Take comfort in knowing that receiving a diagnosis means that your healthcare provider is aware of an abnormality. This information can guide them as they work to keep you and the fetus as healthy as possible. Remember that many people with this diagnosis go on to deliver healthy babies.