Marginal Cord Insertion

Marginal cord insertion (MCI) means the umbilical cord attaches at the edge (margin) of the placenta instead of at the center. It’s a type of abnormal umbilical cord attachment during pregnancy.

With MCI, the umbilical cord is within 2 centimeters or less from the edge of the placenta. The center of the placenta is the most secure place for the cord to attach. It’s less secure when it’s near the edge.

In some — but not all — cases, marginal cord insertion may slow the flow of nutrients from the placenta to the fetus. This can lead to certain complications, like the fetus being smaller than usual. Your pregnancy care provider will monitor you closely to catch any issues as soon as possible.

Symptoms of marginal cord insertion

Marginal cord insertion doesn’t cause symptoms that you can feel. The only way to know whether it affects your pregnancy is with an ultrasound.

Marginal cord insertion causes

Researchers aren’t sure what causes marginal cord insertion. It’s most common in pregnancies involving more than one fetus (like twins or triplets). It affects about 6% of singleton pregnancies (one fetus) and 12% of twin pregnancies.

Other risk factors include:

• Using assisted reproductive technology (ART) to get pregnant, like IVF
• Having long-term high blood pressure before pregnancy
• Giving birth for the first time (nulliparity)
• Having a placenta that covers your cervix (placenta previa)
• Being 35 or older

You can’t control these risk factors. Marginal cord insertion isn’t your fault.

Complications of this condition

Marginal cord insertion can lead to certain complications, including:

• Small fetus size (fetal growth restriction) and birth size (small for gestational age)
• Preeclampsia
• Stillbirth
• The placenta separates from your uterus (placental abruption)
• Birth before 37 weeks of pregnancy (preterm birth)

There’s also an increased risk of neonatal intensive care unit (NICU) admission among pregnancies with MCI. Your baby may need to stay in the NICU to receive extra care until they’re healthy enough to be in the nursery.

Despite these risks of complications, it’s possible to have a typical pregnancy and delivery. In any case, your pregnancy care provider will closely track your pregnancy. This will help them catch any complications as soon as possible.

How doctors diagnose this condition

Healthcare providers diagnose MCI with an ultrasound. They can usually detect it during the second trimester of pregnancy (weeks 14 to 27). Still, it may be tough for your provider to pinpoint exactly where the umbilical cord attaches to the placenta.

Your provider may use the Doppler feature during an ultrasound to see the blood flow between the placenta and fetus. This can help identify the umbilical cord insertion point.

How is it treated?

There’s no treatment for marginal cord insertion. But your healthcare provider may want to monitor your pregnancy more closely. This may include more frequent ultrasounds. It might involve other tests, too, like nonstress tests.

When should I see my healthcare provider?

Your healthcare provider will tell you how often to have follow-up appointments. It may be helpful to ask them the following questions:

• How often will I need ultrasounds?
• Do I need other tests?
• What’s the likelihood that marginal cord insertion will impact my pregnancy?
• Is there anything else I can do to have a healthy pregnancy?

What can I expect if I have this condition?

Each pregnancy is different. Many factors shape the risks involved with any pregnancy. Marginal cord insertion may pose risks, or it may not. Speak to your provider about any concerns you have. They can provide an honest assessment to help guide your pregnancy.