The umbilical artery is the only artery present in the human body, aside from the pulmonary arteries, which carries deoxygenated blood.
Occasionally, there is only the one single umbilical artery (SUA) present in the cord. Approximately 1 in 100 newborns are found to have a SUA, making it the most common umbilical abnormality. It is more common in multiple births. Babies with SUA may have a higher likelihood of having other congenital abnormalities. However, additional testing (high level ultrasound scans) can rule out many of these abnormalities prior to birth and alleviate parental anxiety. Echocardiograms of the fetus may be advised to ensure the heart is functioning properly. Genetic counseling may be useful, too, especially when weighing the pros and cons of more invasive procedures such as chorionic villus sampling and amniocentesis.
It is important to note that a diagnosis of SUA, while anxiety provoking, is in no way a guarantee that a fetus is at risk for other problems in utero or after birth. Especially encouraging are cases in which no other soft markers for congenital abnormalities are visible via ultrasound. Prior to ultrasound technology, the only method for determining the presence of a SUA was at birth, following an examination of the placenta. Given that the vast majority of expectant mothers do not receive the kind of advanced ultrasound scanning required to confirm SUA in utero, most cases may never be detected antenatally even today.
Doctors and midwives often suggest parents take the added precaution of having regular growth scans near term to rule out intrauterine growth restriction, which can happen on occasion and warrant intervention. Yet the majority of growth restricted infants with the abnormality also have other defects. Finally, neonates with the finding may also have a higher occurrence of kidney problems, so close examination of the infant may be warranted shortly after birth. Among SUA infants, there is a slightly elevated risk for post-natal urinary infections.