The presence of a two-vessel cord, also known as a single umbilical artery (SUA), is a relatively common variation in the formation of the umbilical cord. Normally, the umbilical cord contains three vessels: two arteries and one vein. However, in about 1% of pregnancies, the umbilical cord may have only two vessels, with one artery and one vein. This condition can be diagnosed through prenatal ultrasound examinations.
Incidence and Risk Factors
Studies have shown that the incidence of a two-vessel cord can range from 0.5% to 1.4% in the general population. Certain factors may increase the risk of having a baby with a two-vessel cord, including:
- Maternal age: Women over 35 years of age may have a higher risk of having a baby with a two-vessel cord.
- Multiple gestations: Pregnancies involving twins or other multiples may be more likely to have a two-vessel cord.
- Chromosomal abnormalities: Babies with certain chromosomal abnormalities, such as trisomy 18, may be more likely to have a two-vessel cord.
Diagnosis
Diagnosing a two-vessel cord typically occurs during a routine prenatal ultrasound examination. The ultrasound technician will examine the umbilical cord to count the number of vessels present. If only two vessels are seen, further testing may be recommended to rule out any potential complications.
Ultrasound Examination
A prenatal ultrasound examination is a non-invasive test that uses high-frequency sound waves to produce images of the fetus and placenta. During the examination, the ultrasound technician will:
- Measure the umbilical cord: The technician will measure the length and diameter of the umbilical cord to ensure it is within normal ranges.
- Count the vessels: The technician will count the number of vessels present in the umbilical cord. If only two vessels are seen, the technician may take additional measurements to confirm the finding.
- Evaluate the placenta: The technician will examine the placenta to ensure it is functioning properly and providing adequate oxygen and nutrients to the fetus.
Additional Testing
If a two-vessel cord is diagnosed, additional testing may be recommended to monitor the pregnancy and ensure the baby is receiving adequate oxygen and nutrients. This may include:
- Fetal growth scans: Regular ultrasounds to monitor the baby’s growth and development.
- Non-stress tests: Tests to monitor the baby’s heart rate and movements.
- Biophysical profiles: Tests to evaluate the baby’s overall health and well-being.
Complications and Prognosis
While a two-vessel cord can increase the risk of certain complications, many babies with this condition are born healthy and develop normally. Potential complications may include:
- Growth restriction: Babies with a two-vessel cord may be at higher risk for growth restriction, which can increase the risk of complications during delivery.
- Preterm birth: Women with a two-vessel cord may be at higher risk for preterm birth, which can increase the risk of complications for the baby.
- Chromosomal abnormalities: Babies with a two-vessel cord may be at higher risk for certain chromosomal abnormalities, such as trisomy 18.
Management and Delivery
Women with a two-vessel cord should receive regular prenatal care to monitor the pregnancy and ensure the baby is receiving adequate oxygen and nutrients. In some cases, a cesarean delivery may be recommended to reduce the risk of complications during delivery.
Cesarean Delivery
A cesarean delivery may be recommended if:
- Fetal distress: The baby is showing signs of distress, such as a slowed heart rate or decreased movements.
- Growth restriction: The baby is not growing at a normal rate, which can increase the risk of complications during delivery.
- Placental insufficiency: The placenta is not functioning properly, which can increase the risk of complications during delivery.
Conclusion
A two-vessel cord is a relatively common variation in the formation of the umbilical cord. While it can increase the risk of certain complications, many babies with this condition are born healthy and develop normally. Regular prenatal care and monitoring can help identify potential complications early, allowing for prompt intervention and minimizing the risk of adverse outcomes.
What is the incidence of a two-vessel cord in the general population?
+The incidence of a two-vessel cord can range from 0.5% to 1.4% in the general population.
What are the potential complications associated with a two-vessel cord?
+Potential complications may include growth restriction, preterm birth, and chromosomal abnormalities.
How is a two-vessel cord diagnosed?
+A two-vessel cord is typically diagnosed during a routine prenatal ultrasound examination.
