Single umbilical artery

Single umbilical artery

Cross-section of a umbilical cord with a single artery.
Classification and external resources
Specialty	medical genetics
ICD-10	P02.6, Q27.0
ICD-9-CM	747.5
DiseasesDB	34592

Occasionally, there is only the one single umbilical artery (SUA) present in the umbilical cord.^[1] Approximately this affects between 1 in 100 and 1 in 500 pregnancies, making it the most common umbilical abnormality. It is more common in multiple births. Its cause is not known.

Most cords have one vein and two arteries. The vein carries oxygenated blood from the placenta to the baby and the arteries carry deoxygenated blood from the baby to the placenta. In approximately 1% of pregnancies there are only two vessels —usually a single vein and single artery. In about 75% of those cases, the baby is entirely normal and healthy and the missing artery isn't missed at all. One artery can support a pregnancy and does not necessarily indicate problems. For the other 25%, a 2-vessel cord is a sign that the baby has other abnormalities—sometimes life-threatening and sometimes not.^[2] SUA does increase the risk of the baby having cardiac, skeletal, intestinal or renal problems.^[3] Babies with SUA may have a higher likelihood of having other congenital abnormalities, especially of the heart. 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.

Although the presence of an SUA is a risk factor for additional complications, most fetuses with the condition will not experience other problems, either 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 renal problems, therefore 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.

It may be associated with Edwards syndrome.

References

↑ Geipel A, Germer U, Welp T, Schwinger E, Gembruch U (February 2000). "Prenatal diagnosis of single umbilical artery: determination of the absent side, associated anomalies, Doppler findings and perinatal outcome". Ultrasound Obstet Gynecol. 15 (2): 114–7. doi:10.1046/j.1469-0705.2000.00055.x. PMID 10775992.
↑ http://www.fitpregnancy.com/labor-delivery/ask-labor-nurse/two-reasons-worry
↑ http://www.nhs.uk/chq/pages/2299.aspx?categoryid=54&subcategoryid=128

Certain conditions originating in the perinatal period / fetal disease (P, 760–779)

Maternal factors and
complications of pregnancy,
labour and delivery

placenta:	Placenta praevia Placental insufficiency Twin-to-twin transfusion syndrome

chorion/amnion:	Chorioamnionitis

umbilical cord:	Umbilical cord prolapse Nuchal cord Single umbilical artery

Length of gestation
and fetal growth

Birth trauma

By system

Respiratory	Intrauterine hypoxia Infant respiratory distress syndrome Transient tachypnea of the newborn Meconium aspiration syndrome pleural disease Pneumothorax Pneumomediastinum Wilson–Mikity syndrome Bronchopulmonary dysplasia

Cardiovascular	Pneumopericardium Persistent fetal circulation

Haemorrhagic and hematologic disease	Vitamin K deficiency Haemorrhagic disease of the newborn HDN ABO Anti-Kell Rh c Rh D Rh E Hydrops fetalis Hyperbilirubinemia Kernicterus Neonatal jaundice Velamentous cord insertion Intraventricular hemorrhage Germinal matrix hemorrhage Anemia of prematurity

Digestive	Ileus Necrotizing enterocolitis Meconium peritonitis

Integument and thermoregulation	Erythema toxicum Sclerema neonatorum

Nervous system	Periventricular leukomalacia

Musculoskeletal	Gray baby syndrome muscle tone Congenital hypertonia Congenital hypotonia

Infectious

Other

Congenital vascular defects / Vascular malformation (Q25–Q28, 747)

Great arteries/
other arteries

Aorta	Patent ductus arteriosus Coarctation of the aorta Interrupted aortic arch Double aortic arch Right-sided aortic arch Overriding aorta Aneurysm of sinus of Valsalva Vascular ring

Pulmonary artery	Pulmonary atresia Stenosis of pulmonary artery

Subclavian artery	Aberrant subclavian artery

Umbilical artery	Single umbilical artery

Great veins

Superior/inferior vena cava	Congenital stenosis of vena cava Persistent left superior vena cava

Pulmonary vein	Anomalous pulmonary venous connection (Total, Partial) Scimitar syndrome

Arteriovenous malformation

Cerebral arteriovenous malformation

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