Single Umbilical Artery in Pregnancy
Single umbilical artery, also called a two-vessel cord, means the umbilical cord has one artery and one vein instead of the usual two arteries and one vein. Many cases are isolated, but a detailed fetal medicine scan is important to check the heart, kidneys, abdomen, growth and placenta.
Doctor-led review after a two-vessel cord finding
A report mentioning “single umbilical artery” or “two-vessel cord” can worry parents, especially when it is found during the anomaly scan. The first step is to determine whether this is an isolated cord finding or whether there are associated concerns in the heart, kidneys, gastrointestinal tract, limbs, growth or placenta.
Dr. Kunda Shahane performs a structured fetal medicine review and explains whether reassurance, fetal echo, genetic counselling, third-trimester growth follow-up or closer surveillance is needed.
What is a single umbilical artery?
Normally the umbilical cord has three vessels: two arteries and one vein. In SUA, one artery is absent.
Usual cord anatomy
A usual umbilical cord has two arteries that carry blood from the baby to the placenta and one vein that carries oxygen-rich blood back to the baby.
Two-vessel cord
In single umbilical artery, the cord has one artery and one vein. This is why the report may call it a two-vessel cord.
Isolated or associated
If the rest of the fetal scan is normal, SUA is called isolated. If another anomaly or growth concern is present, the evaluation and counselling change.
Important message for parents
Single umbilical artery does not automatically mean the baby has a major problem. Many isolated cases have a good outcome. But it should not be ignored — a careful anomaly scan, heart review and growth follow-up are important.
What Dr. Kunda evaluates in single umbilical artery
The scan is designed to confirm the cord finding and rule out associated concerns.
| Assessment area | What is checked | Why it matters |
|---|---|---|
| Cord vessel confirmation | One artery One vein Bladder-side Doppler | Colour Doppler around the fetal bladder helps confirm that one umbilical artery is absent. |
| Fetal heart screening | Four-chamber view, outflow tracts, three-vessel view, rhythm and cardiac position. | SUA can be associated with cardiac anomalies, so the heart must be reviewed carefully. |
| Fetal echocardiography | Detailed heart scan when cardiac views are suboptimal, any heart concern is present, or local protocol recommends it. | Fetal echo gives a more focused assessment of fetal heart structure and rhythm. |
| Kidneys and urinary tract | Kidneys, renal pelvis, bladder filling, ureters and amniotic fluid volume. | Renal and urinary tract anomalies are among the important associated findings to exclude. |
| Gastrointestinal and abdominal review | Stomach, bowel, abdominal wall, liver, gall bladder and abdominal circumference. | GI and abdominal anomalies are checked because SUA may be associated with other structural findings. |
| Limbs, spine and face | Long bones, hands, feet, spine, facial profile and other anomaly scan views. | A complete structural survey helps decide whether SUA is truly isolated. |
| Placenta and cord insertion | Placental site, cord insertion, marginal or velamentous insertion, amniotic fluid. | Cord insertion details help with growth monitoring and pregnancy planning. |
| Fetal growth | BPD/HC AC FL EFW trend | Isolated SUA can be associated with fetal growth restriction, so serial growth scans are commonly advised. |
| Genetic counselling context | NT scan, first-trimester screening, NIPT/cfDNA, family history and associated markers/anomalies. | Genetic testing is usually considered when SUA is not isolated or screening risk is increased. |
The most important distinction: isolated vs non-isolated SUA
When SUA is isolated, and the detailed fetal scan and screening are reassuring, counselling is usually more positive. The main plan is generally serial growth monitoring and third-trimester follow-up.
When SUA is seen with another anomaly, abnormal heart view, renal finding, growth restriction or increased screening risk, the pregnancy needs deeper fetal medicine evaluation, fetal echocardiography and genetic counselling.
What happens after SUA is detected?
The plan depends on whether SUA is the only finding or part of a wider fetal pattern.
Confirm the two-vessel cord
Colour Doppler around the fetal bladder and cord imaging are used to confirm one umbilical artery and one vein.
Perform a detailed anomaly review
The scan checks fetal heart, kidneys, abdomen, limbs, spine, brain, face, placenta and cord insertion.
Decide whether fetal echo is needed
Fetal echocardiography is advised if cardiac views are incomplete, any heart concern is seen, SUA is non-isolated, or a detailed heart review is clinically preferred.
Review genetic screening
NT scan, double marker, NIPT/cfDNA or other screening results are reviewed. Diagnostic testing is discussed mainly when SUA is not isolated or other risk factors are present.
Plan third-trimester growth monitoring
Serial growth scans help monitor estimated fetal weight, abdominal circumference, amniotic fluid, Doppler when needed and overall fetal wellbeing.
Why growth monitoring matters in SUA
Even when SUA is isolated, later pregnancy follow-up helps ensure the baby continues to grow well.
Estimated fetal weight
Growth scan tracks whether the baby’s weight estimate is following the expected centile.
Abdominal circumference
AC is useful because early placental or growth concerns may show as slowing abdominal growth.
Doppler when needed
Umbilical artery, MCA or other Dopplers may be added if fetal growth restriction or placental insufficiency is suspected.
Antenatal surveillance
Later pregnancy fetal surveillance may be considered depending on growth, Doppler, obstetric history and treating doctor’s plan.
When counselling is more reassuring
Counselling is generally more reassuring when SUA is isolated, fetal anatomy is otherwise normal, heart views are good, kidneys are normal, screening is low risk, amniotic fluid is normal and fetal growth remains appropriate.
When should you seek an SUA second opinion?
After anomaly scan
If your scan report says single umbilical artery, two-vessel cord, absent right umbilical artery or absent left umbilical artery.
If anatomy was incomplete
If heart, kidney, abdominal, spine or limb views were not clearly seen, a specialist fetal medicine review is useful.
For growth planning
If you need a clear third-trimester growth scan schedule or Doppler plan after SUA was detected.
What to bring for the visit
Bring previous ultrasound reports, anomaly scan images if available, NT scan report, first-trimester screening or NIPT report, obstetric notes, fetal echo report if already done, and any referral letter from your doctor.
Dr. Kunda Shahane’s note on single umbilical artery
“When single umbilical artery is seen, the most important question is not just the cord count. We must confirm whether the baby’s anatomy is otherwise normal, especially the heart and kidneys, and then monitor growth later in pregnancy. If the finding is isolated, counselling can often be much more reassuring.”
Single umbilical artery FAQs
What does two-vessel cord mean?
Two-vessel cord means the umbilical cord has one artery and one vein instead of two arteries and one vein. This is the same as single umbilical artery.
Does SUA mean the baby definitely has a problem?
No. Many cases are isolated and babies do well. The concern is higher when SUA is seen with other anomalies, abnormal growth, abnormal heart findings or high-risk screening.
Why is the heart checked carefully in SUA?
SUA can be associated with cardiac anomalies. A detailed anomaly scan checks the fetal heart, and fetal echocardiography may be advised if there is any concern or incomplete heart view.
Why are kidneys checked in SUA?
Renal and urinary tract anomalies can be associated with SUA. The scan checks both kidneys, bladder filling, renal pelvis and amniotic fluid.
Do I need amniocentesis for isolated SUA?
If SUA is isolated and previous screening is low risk, invasive testing may not be required. If other anomalies or markers are present, genetic counselling and diagnostic testing may be discussed.
How many growth scans are needed?
The follow-up schedule depends on the detailed scan findings, fetal growth, placental findings and obstetric history. A third-trimester growth scan is commonly planned, with Doppler added if needed.
Can SUA affect delivery?
Isolated SUA does not automatically mean cesarean delivery. Delivery planning depends on fetal growth, Doppler, obstetric factors and the treating obstetrician’s advice.
Will the cord become normal later?
No. If one umbilical artery is truly absent, the cord anatomy does not change. What matters is whether the baby’s anatomy and growth remain reassuring.
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Need single umbilical artery counselling in Nagpur?
Book a detailed fetal medicine scan and counselling appointment with Dr. Kunda Shahane at Mayflower Fetal Medicine & High-Risk Pregnancy Centre, Dhantoli, Nagpur. Bring your anomaly scan and previous screening reports so the finding can be interpreted correctly.
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