What Every Pregnant Woman Should Know About Umbilical Cord Insertion
- Anita Grewal
- Oct 7
- 4 min read
When it comes to prenatal health, there’s one lesser-known but important aspect many expectant mothers have never heard of: umbilical cord insertion. Despite its significance,
examining where and how the umbilical cord attaches to the placenta is not routinely part of standard prenatal ultrasounds in many countries. Often, abnormalities in cord insertion are only identified after birth—or worse, after complications arise.
But why is this detail so important? And should pregnant women advocate for it to be checked?
My Story: From Surprise Diagnosis to Heartbreaking Loss
During my fourth pregnancy, I was diagnosed with a condition called marginal cord insertion at my 20-week detailed anatomy scan. At the time, I was told not to worry—my doctor reassured me that it typically does not lead to adverse perinatal outcomes. The baby’s growth was on track, and everything seemed fine.
Sadly, at 27 weeks, I lost my baby. While marginal cord insertion was not listed as the primary cause, it was included as one of the possible contributing factors to the stillbirth.
When I became pregnant again, the experience left me deeply cautious. At 15 weeks into my fifth pregnancy, the sonographer proactively examined the cord insertion site due to my history. Alarmingly, the cord again appeared to be marginal. At the 20-week scan, it was measured more accurately—4.9 cm away from the placental edge—and reclassified as an eccentric cord insertion, which is typically considered normal.
This repeated pattern led me down a rabbit hole of research, trying to understand why I had two abnormal insertions in a row, despite no apparent risk factors.
What Is Umbilical Cord Insertion?
The umbilical cord is the lifeline between the placenta and the developing baby. It delivers oxygen, nutrients, and removes waste products. Ideally, the cord inserts into the center of the placenta, ensuring optimal distribution of nutrients and blood flow.
However, in some pregnancies, the cord inserts at less-than-ideal locations, which may pose risks to the baby, particularly later in gestation.
Types of Cord Insertion:
Central Insertion – Ideal location, at the center of the placenta.
Eccentric Insertion – Slightly off-center, but generally not problematic (>2 cm from the edge).
Marginal Insertion – At or within 2 cm of the placental edge. May increase the risk of complications.
Velamentous Insertion – The cord inserts into the fetal membranes rather than directly into the placenta. Blood vessels are exposed and vulnerable. This is the most dangerous form.
It’s worth noting that the terms eccentric and marginal are sometimes used interchangeably, particularly if precise measurements aren’t taken. However, in clinical terms, only marginal and velamentous insertions are considered abnormal.
How Common Are These Conditions?
Marginal cord insertion occurs in about 7% of singleton pregnancies and up to 25% of twin pregnancies.
Velamentous insertion is rarer, affecting roughly 1% of singleton pregnancies.
Central and eccentric insertions are the most common and typically don’t cause complications.
Is There a Pattern? What Research (and Mothers) Are Saying
What surprised me most in my research was how common marginal insertions seem to be—and yet how little is known about why they happen.
Many mothers in forums and support groups reported repeat occurrences across multiple pregnancies, much like I experienced. Some had marginal insertion in all four of their pregnancies. Others had it only once. So far, research suggests the condition may be sporadic, but there is emerging evidence that a history of abnormal cord insertion increases the risk of recurrence in future pregnancies.
Known Risk Factors for Abnormal Cord Insertion:
Twin or multiple pregnancies
Advanced maternal age
Assisted reproductive technologies (e.g., IVF)
Uterine anomalies
But in many cases, no clear cause can be found. It can simply be the result of how the placenta develops during early pregnancy.
Why Marginal and Velamentous Insertions Matter
While marginal insertion is often managed successfully, it’s not completely benign. It has been associated with:
Low birth weight
Preterm delivery
Placental abruption
Intrauterine growth restriction (IUGR)
Even more concerning is that marginal insertion can progress into velamentous insertion later in pregnancy due to placental trophotropism—the natural growth and remodeling of the placenta.
Velamentous insertion carries significant risks, including:
Fetal distress
Vasa previa (a life-threatening condition where fetal vessels cross the cervix)
Stillbirth
Hemorrhage during delivery
The Importance of Monitoring
Although there is no treatment for abnormal cord insertions, careful monitoring can dramatically improve outcomes. In my case, increased surveillance may not have changed the outcome, but it empowered me with more knowledge during my next pregnancy.
Recommended Management Strategies:
Regular ultrasounds to monitor fetal growth
Cardiotocography (CTG) from around 28 weeks or earlier if advised
Fetal kick counting
Nutrient-rich diet and prenatal supplements
Low-dose aspirin (if prescribed by your doctor)
Sleeping on the left side to maximize blood flow
Light to moderate exercise
Acupuncture (some evidence suggests it may increase blood flow)
Early delivery planning (some mothers opt for elective C-section if risks escalate)
One Mother’s Story—and the Lesson in Advocacy
In my research, I came across a heartbreaking story online of a mother who lost her baby due to placental abruption linked to marginal cord insertion. Her loss may have been prevented through earlier monitoring and delivery planning.
The reality is, you are your baby’s best advocate. If you have a history of complications, ask questions, push for closer monitoring, and insist on checking the cord insertion during your anatomy scan, especially if it’s not done routinely.
Final Thoughts: Knowledge Is Power
Umbilical cord insertion may seem like a small detail—but in some pregnancies, it can make all the difference. While most marginal insertions do not cause problems, being aware, informed, and proactive can give your baby the best chance at a healthy start.
If you're currently pregnant or planning to be, speak with your healthcare provider about including cord insertion assessment in your ultrasound. It’s a simple addition that could have a significant impact.
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