Single Umbilical Artery Problems
Umbilical Cord Blood Vessel Issues Caused by Missing Artery
Nov 6, 2009
A fetus diagnosed with a single umbilical artery can be worrying for the mother-to-be, but most of these cases turn out just fine. Major problems associated with the loss of an artery in the umbilical cord are usually linked to other markers visible on ultrasound or through tests such as amniocenteisis.
What is a Single Umbilical Artery?
Normally, an umbilical cord has three vessels. One is a vein and two are arteries. The vein carries blood away from the fetus and back to the mother's bloodstream via the placenta, while the arteries carry mom's nutrient-rich blood from the placenta to the developing baby. In a pregnancy with a single umbilical artery, one of the two umbilical cord arteries is missing, leaving only one vein and one artery.
Is a Single Umbilical Artery Dangerous?
Having a single umbilical artery can lead to an increased risk of birth defects, but these are usually associated with other signs as well. Doctors using ultrasound can spot chromosomal abnormalities that may be associated with the loss of an umbilical artery. The pregnant woman will then be referred for further testing through tests like amniocentesis or chorionic villus sampling.
If the fetus doesn't have any other problems seen via ultrasound or through amniocentesis, then problems due to a single umbilical artery are not likely to occur. However, sometimes the doctor will want to order extra ultrasounds throughout the pregnancy just to be on the safe side. This can help rule out instances of intrauterine growth restriction (IUGR), when the baby's blood supply is not providing enough nutrients for proper growth, which might occur due to abnormal umbilical cord blood vessels.
How Common is a Single Umbilical Artery?
One percent of single births and about five percent of pregnancies carrying twins or other multiples have the problem of the fetus developing only a single umbilical artery. The incidence of single umbilical arteries is higher in Caucasian women and in female babies. Mothers older than 40 and those who have had more than three children also are in a higher risk group for their baby to develop this condition. Doctors may wish to follow up more frequently with pregnant women who are in these high-risk groups.
Although the presence of a single umbilical artery can be worrying for pregnant women and their doctors, most cases can be monitored and followed up on easily with modern ultrasound and testing procedures. Along with most other umbilical cord problems, it's important to remember that the majority of babies with a single umbilical artery and no other symptoms turn out just fine and the lack of one blood vessel doesn't seem to harm them in any way.
Sources:
Benirschke K and Bourne GL.The incidence and prognostic implication of congenital absence of one umbilical artery. Am J Obstet Gynecol. 1960 Feb;79:251-4
Catanzarite VA, aet al., Prenatal diagnosis of the two-vessel cord: implications for patient counselling and obstetric management.Ultrasound Obstet Gynecol. 1995 Feb;5(2):98-105.
Mary King, MD, et al. Management of Pregnancy Complicated by Single Umbilical Artery Medscape
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