Maternité Rita Merli, Hôpital Saint Damien, Nos Petits frères et sœurs 
Maternité Isaïe Jeanty et Léon Audain

Case report
Following images represent a case of single umbilical artery.

The absence of one of the arteries in the umbilical cord is called single umbilical artery (SUA) or two-vessel umbilical cord. The pathogenesis of SUA is uncertain. Aplasia or atrophy of the missing vessel has been suggested as an etiology of SUA. SUA is one of the most common sonographic findings during pregnancy and is more commonly seen in multiple gestations, in the presence of velamentous cord insertion, in advanced maternal age, in maternal diabetes, in hypertensive and seizure disorders, and in smoking. Detection of SUA is best performed by obtaining an axial plane of the fetal pelvis in color Doppler and identifying a SUA next to the bladder, rather than the two umbilical arteries normally seen.

The association of SUA with fetal anomalies, mainly genitourinary and cardiac, as well as with a wide range of genetic syndromes and chromosomal aberrations has been reported. SUA can also be associated with intrauterine growth restriction, preterm delivery, and poor pregnancy outcome.

U.V - Umbilical vein ; U.A. - Umbilical arteries ; B - Bladder

References

First Trimester Ultrasound Diagnosis of Fetal Abnormalities 
Alfred Abuhamad, Rabih Chaoui, First edition, 2018