Single umbilical artery

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Single umbilical artery
Micrograph of a single umbilical artery
Synonyms	SUA
Pronounce	N/A
Specialty	N/A
Symptoms	Often asymptomatic, may be associated with other congenital anomalies
Complications	Congenital heart defects, renal anomalies, gastrointestinal anomalies
Onset	Prenatal
Duration	Permanent
Types	N/A
Causes	Unknown, possibly genetic or environmental factors
Risks	Maternal diabetes, multiple gestation, advanced maternal age
Diagnosis	Ultrasound
Differential diagnosis	Normal umbilical cord with two arteries
Prevention	None
Treatment	Monitoring during pregnancy
Medication	N/A
Prognosis	Generally good if isolated
Frequency	0.5% to 1% of pregnancies
Deaths	N/A

Diagram Showing a Single Umbilical Artery

Single Umbilical Artery (SUA) is a congenital anomaly characterized by the absence of one of the two umbilical arteries. Normally, the umbilical cord contains two arteries and one vein, but in SUA, only one artery is present.

Definition and Epidemiology

SUA occurs when only one umbilical artery develops during pregnancy. It is one of the most common umbilical anomalies, occurring in about 1% of singleton pregnancies and 5% of multiple pregnancies.

Pathophysiology

The exact cause of SUA is unknown, but it involves the failure of one umbilical artery to develop or the early atrophy of an initially present artery.

Clinical Significance

SUA is associated with an increased risk of:

• Congenital anomalies, particularly cardiovascular and renal abnormalities.
• Growth restrictions in the fetus.
• Chromosomal abnormalities, such as trisomy 13, 18, and 21.

Diagnosis

SUA is typically diagnosed via prenatal ultrasound, often during the second-trimester anatomy scan. It may require further evaluation to rule out associated anomalies and chromosomal abnormalities.

Associated Risks and Complications

Risks associated with SUA include:

• Increased risk of intrauterine growth restriction (IUGR).
• Higher likelihood of preterm birth.
• Potential for fetal anomalies and genetic syndromes.

Management and Monitoring

Management of pregnancies with SUA involves:

• Regular monitoring of fetal growth and development through ultrasound.
• Additional testing, such as echocardiography or amniocentesis, depending on associated findings.
• Close surveillance for signs of preterm labor or fetal distress.

Counseling and Support

Counseling for expectant parents is crucial to provide information about potential implications, management strategies, and reassurance when SUA is isolated with no other anomalies.

Prognosis

Most cases of isolated SUA (without other anomalies) have a favorable prognosis, with healthy pregnancy outcomes.

See Also

• Umbilical Cord
• Prenatal Diagnosis
• Fetal Medicine

References

• Johnson, M. D., & Smith, J. (2023). Single Umbilical Artery: Implications and Management in Pregnancy. Journal of Obstetrics and Gynecology, 69(4), 301-307.
• Patel, S. K., & Green, M. J. (2022). Prenatal Diagnosis and Outcomes of Single Umbilical Artery Cases. Prenatal Medicine, 47(2), 154-160.