What is a single umbilical artery?
A normal umbilical cord contains one vein and two arteries, carrying blood and oxygen to the fetus and waste products away from the fetus. In some pregnancies, the umbilical cord has only one artery instead of the usual two (photos). Single umbilical artery (SUA) is found in about 1% of single fetus pregnancies and aobut 5% of multiples pregnancies. SUA is thought to be caused by atrophy or lack of development of the second artery.
Some studies suggest that SUA babies have an increased risk of abnormalities, birth defects, and small gestational age infants (intrauterine growth restriction, IUGR). However, there is still no consensus on the clinical importance of SUA. Prenatal tests including detailed ultrasounds can help test for birth defects. Patient counseling is very important so the parents are aware of the possible malformations even if the ultrasound does not reveal any abnormalities. If your doctor determines that further tests are necessary, an amniocentesis can provide additional information (the doctor removes amniotic fluid from the uterus to perform tests).
- March of Dimes: Pregnancy Complications – Umbilical cord abnormalities
- Medscape: Management of Pregnancy Complicated by Single Umbilical Artery
- Emedicine: Single Umbilical Artery
- Obfocus: Single umbilical artery
- Obstetrics & Gynecology: Single Umbilical Artery and Its Associated Findings
- Mayo Clinic: Amniocentesis