The umbilical cord is a kind of tube that joins the belly button of the fetus with the mother's placenta. It is formed by a vein and two arteries. But it may happen that only one, malformation that is known by the name of single umbilical artery.
We tell you when it occurs, why it occurs and how it affects pregnancy and the baby.
What is the unique umbilical artery?
The vein that contains the umbilical cord carries oxygen and nutrients from the placenta to your baby, while the two arteries return your baby's waste products to the placenta. Then, the placenta transfers these wastes to the mother's blood, which is responsible for removing them.
The single umbilical artery (SUA) is characterized by the absence of the left or right umbilical artery, as detailed in the meta-analysis' Risk factors and neonatal outcomes of the single umbilical artery isolated in the single pregnancy ', published in the scientific journal' Nature ', and that is the last study conducted on this malformation.
In Babies and more Pregnancy tests: detection of chromosomal abnormalities Are there risk factors?
Although statistics vary depending on where the study was conducted, it is said that One percent of pregnancies present the problem. In addition, the incidence is 3-4 times higher in multiple pregnancies. than in single pregnancies.
According to Natura's meta-analysis, studies suggest many risk factors for SUA: advanced age of the mother, ethnicity (more common in white women), multiparity and multiple gestation.
It is also associated with chromosomal abnormalities, especially trisomy 18 or Edwards syndrome.
In Babies and more Genetics: genes and chromosomesToday it is unknown what causes the baby's cord to develop only with an artery, so it is impossible to prevent this anomaly.
How is the single umbilical artery diagnosed?
Typically, it is detected on the detailed ultrasound performed around the 20th week of pregnancy. But it can be diagnosed before or after the ultrasound of the 20 weeks, since the correct functioning of the cord is checked routinely in the ultrasound controls.
The detection of this anomaly is even easier thanks to the Doppler ultrasound, sonograms that allow the blood flow to be identified with colors, showing if the cord has two arteries or only one.
In Babies and more Ultrasound in pregnancyAlthough not usually performed routinely, it can be recommended towards the end of pregnancy, in the last trimester, to measure and evaluate the flow of blood the baby receives through the umbilical cord.
What consequences does it have for the baby?
In the case of a single umbilical artery, the only existing artery also works for the other. In fact, its size is larger than normal.
Although the most recent meta-analysis, based on 57 studies, did not find a relevant association between this malformation and others without chromosomal alterations, SUA does seem to frequently involve certain obstetric complications, such as low birth weight, premature delivery and low Apgar test score.
But also, in some very specific cases, it can affect the health of the kidneys, digestive system or the baby's heart during pregnancy. To rule out possible abnormalities in these organs, the obstetrician will monitor them more closely, performing an echocardiogram of the baby's heart, or even with an amniocentesis.
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