Single Umbilical Artery

Resmy Palliyil Gopi

Umbilical cord

2 umbilical arteries 1 umbilical vein Rudimentary allantois Remnant of omphalomesenteric duct Whartons jelly

Incidence

Most common congenital malformation of the umbilical cord

5-10 in 1000 births (35-70 in 1000 twin births)

Left artery tends to be absent more often than the right

More common in Caucasian women

Conditions associated with single umbilical artery

Advanced maternal age Multiparity Maternal diabetes Hypertension / toxemia Ante partum hemorrhage Poly/oligo hydramnios

Pathogenesis

Primary agenesis Secondary atrophy or atresia of a previously

normal umbilical artery Persistence of the original allantoic artery of

the body stalk

Classification of SUA

Type

# of patent vessels

Consists of Frequency

I two One UA (allantoic) and left UV

Common

II two One UA (vitelline) and left UV

Rare

III three One UA and both UV Very rare

IV two One UA and right UV Very rare

Associated prenatal complications

Isolated (1/2 to 2/3rd) Associated congenital malformations (30%)

– Fetal structural abnormalities– Chromosomal abnormalities (trisomy 18/13)– Genetic syndromes (VATER, sirenomelia sequence) – IUGR– Prematurity– Still birth and spontaneous abortions– Placental abnormalities

Diagnosis

prenatal– Ultrasound (only two vessels are seen and artery is

abnormally large)– Color Doppler

postnatal– Examination of the cord

Color Doppler

Management considerations

Detailed ultrasonographic examination Fetal echocardiography Fetal genetic testing Enhanced fetal surveillance

– Serial ultrasound to assess fetal growth– Biophysical profile, NST

Physical evaluation of the neonate Neonatal renal ultrasonography

Prognosis

- depends on the associated anomalies Recurrence risk

- Unknown

Abnormalities of the umbilical cord

Abnormalities of the cord length and diameter

– Short cords and long cords

Abnormalities of the umbilical cord

Distortional abnormalities– loops, knots (true or false), torsions

and twists

True knot

False knot

Twist

Other abnormalities of the umbilical cord

Neoplasms of the umbilical cord

– Thrombosis, hemangioma, hematoma, teratoma

edema

Velamentous insertion of the umbilical cord

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