What are the other Names for this Condition? (Also known as/Synonyms)

• SUA (Single Umbilical Artery)

What is Single Umbilical Artery? (Definition/Background Information)

• The umbilical cord contains two umbilical arteries and one umbilical vein, providing a connection between maternal and fetal blood circulation
• In Single Umbilical Artery (SUA), there is only one umbilical artery, which affects the blood supply between the mother and the developing fetus. Typically, the condition is associated with miscarriages and stillbirths
• The placenta is an organ that connects the developing fetus to the uterine wall. It is a disc shaped reddish brown structure that connects the fetus to the mother through the umbilical cord
• The normal function of placenta is to supply nutrients and oxygen to the fetus from the mother’s blood and remove wastes from the fetal body
• Pregnant women with diabetes and the presence of genetic abnormalities (Trisomies) in the fetus are some of the risks for a Single Umbilical Artery
• There are multiple congenital defects associated in infants born with a Single Umbilical Artery such as spina bifida, heart anomalies, and webbed or multiple fingers
• Single Umbilical Artery requires prompt and emergency treatment for an improved prognosis. However, the fetal morbidity and mortality is high
• Currently, there are no preventative measures available for Single Umbilical Artery

Who gets Single Umbilical Artery? (Age and Sex Distribution)

• Single Umbilical Artery may occur in pregnant women of all ages. The incidence is estimated at less than 1 in 100 pregnancies
• Women who are pregnant with both male and female fetuses can be affected
• All racial and ethnic groups may be affected, but a higher incidence rate is noticed among Caucasian women over Afro-American or Asian women

What are the Risk Factors for Single Umbilical Artery? (Predisposing Factors)

The risk factors for Single Umbilical Artery may include:

• Maternal diabetes
• Chromosomal abnormalities such as trisomy 13 and trisomy 18
• Presence of twins: There is a controversy whether SUA occurs to a higher degree in twins. While some studies have shown a higher incidence of the condition among twin pregnancies, other studies have not corroborated the same
• Velamentous or marginal insertion of the umbilical cord

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Single Umbilical Artery? (Etiology)

• The exact cause of Single Umbilical Artery is unknown
• An abnormal development of the umbilical cord during pregnancy, may be a possible cause

What are the Signs and Symptoms of Single Umbilical Artery?

The signs and symptoms of Single Umbilical Artery may include:

• Decreased blood flow to the fetus resulting in fetal distress
• SUA is associated with a variety of birth defects that may be revealed on a prenatal imaging scan

How is Single Umbilical Artery Diagnosed?

The diagnosis of Single Umbilical Artery may involve:

• Physical examination along with an evaluation of one’s medical history: The healthcare provider may check for any signs of fetal distress (such as non-reassuring fetal heart rate)
• Prenatal abdominal ultrasound may reveal the condition and other associated fetal abnormalities
• A careful examination of the placenta by a pathologist after birth of the child, to macroscopically (gross visual exam) and microscopically analyze the placental tissue may help establish a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Single Umbilical Artery?

Complications due to Single Umbilical Artery may include:

• Premature labor
• Intrauterine growth retardation (IUGR)
• SUA is generally associated with low birth weight
• Increased incidence of neonatal death and stillbirths
• Counseling for the parents who may suffer severe emotional distress

Infants born from a Single Umbilical Artery pregnancy can have a number of fetal abnormalities that may include:

• Multiple fingers (polydactyly); fused, webbed fingers (syndactyly)
• Cleft lip
• Cystic hygroma
• Spina bifida
• Ventricular septal defect (VSD)
• The presence of kidney defects, which may remain asymptomatic until the baby grows. Hence, an ultrasound scan study of the abdomen of the newborn should be considered

How is Single Umbilical Artery Treated?

• Single Umbilical Artery is a medical emergency and the treatment is directed at saving the fetus and managing the associated complications
• A careful and periodic monitoring of the pregnancy is necessary, since the presence of SUA is considered to be a high-risk pregnancy

How can Single Umbilical Artery be Prevented?

• Currently, there are no definitive methods available to prevent Single Umbilical Artery
• A careful and periodic monitoring of the pregnancy is advised and recommended

What is the Prognosis of Single Umbilical Artery? (Outcomes/Resolutions)

• Single Umbilical Artery can be a life-threatening condition with a high mortality rate. In many cases, it may result in the termination of the pregnancy or a stillbirth
• After birth of the baby, the baby should be evaluated for heart defects and genetic abnormalities
• It is observed that about one-third of the children have chromosomal defects such as trisomy 13 and trisomy 18

Additional and Relevant Useful Information for Single Umbilical Artery:

Trisomy 21 causing Down syndrome is not common among babies born with Single Umbilical Artery.