Umbilicus – Single Umbilical Artery

Differential Diagnosis

• Developmental agenesis or hypoplasia
  –No clear sex ratio
  –Males more likely to have associated malformations
  –Increased incidence in twins, either mono- or dizygotic
  –Increased incidence of placental anomalies
  –More common in low birth weight infants
  –More common in premature infants

• Associated maternal factors
  –Maternal diabetes
  –Maternal epilepsy
  –Toxemia
• Intrauterine thrombosis of other umbilical artery

• Malformations are associated with SUA in 45% of cases
  –Genitourinary (33%): Renal agenesis, dysgenesis, hypoplasia; ambiguous genitalia
  –Musculoskeletal (37%): Clubfoot, vertebral anomalies
  –Cardiovascular (30%): Patent ductus arteriosus, ventricular septal defect, dextrocardia
  –Gastrointestinal (28%): Imperforate anus, tracheoesophageal fistula
  –Respiratory (9%): Pulmonary hypoplasia (malformations due to disruption of blood flow), sirenomelia

• Chromosomal anomalies
  –Trisomy 18

Workup and Diagnosis

• History
  –Prenatal tests such as amniocentesis with karyotype
  –Twinning
• Physical exam
  –Dysmorphic facial features
  –Anomalies with genitourinary, gastrointestinal, cardiac, musculoskeletal organ systems
  –Neurologic signs associated with stroke (e.g., seizures)
• Level II prenatal ultrasound with Doppler examination of umbilical cord
• Examination of placenta and cord at delivery
  –Examine closer to umbilical end of cord since vessels may merge close to placental insertion
• Karyotype
• Genetics consultation
• Thrombophilia evaluation
  –Factor V Leiden or antithrombin III deficiency
  –Anticardiolipin or lupus anticoagulant

Treatment

• No treatment if anomaly is isolated
• Treat GI obstruction or urologic anomalies accordingly
• Many infants with chromosomal anomalies are stillborn or die soon after birth
• Genetic counseling regarding possible future risk associated with chromosomal anomalies