Single Artery Umbilical Cord | The Risks and Fears

The big scan – something nearly every pregnant mother looks forward to. Who is it, that has been growing in your belly for the last 18-20 weeks?

This scan is known as the anatomy scan. Many can’t wait to see a clear profile shot, and others are overjoyed to find out if they will be having a boy or a girl.

While breathtaking pictures and finding out the sex are what come to mind for the big scan, the purpose of the scan is to check out fetal development and growth.

Occasionally, a provider might find a fetal, umbilical, or placental abnormality. One of the possible abnormalities is a single artery umbilical cord (SUA).

Anytime you hear “abnormality” in relation to your pregnancy, it can cause a great deal of worry.

But what is a single artery umbilical cord exactly? Does it mean you or your baby are at risk for complications?

What Is A Single Artery Umbilical Cord?

The umbilical cord is the lifeline between you and baby. During typical development, an umbilical cord has three vessels. One vein which brings your baby oxygen and nutrients, and two arteries which carry away waste from your baby to be processed via your kidneys.

A single artery umbilical cord has only two vessels. A single artery umbilical cord means your baby only has one blood vessel in the umbilical cord instead of two. Normally, there are two arteries and one vein in the cord which carry oxygenated and deoxygenated blood between the placenta and your baby. With only one artery, there is concern that the blood flow could be restricted, potentially limiting your baby’s growth and development during pregnancy. A single artery umbilical cord is also known as a two vessel cord.

Around 1% of pregnancies have a SUA, and just under 5% of twin and multiple pregnancies have a SUA. It’s the most common umbilical abnormality. The good news is that most of the time, pregnancies with a single artery umbilical cord proceed normally and result in the birth of healthy babies.

Fears and Risks

However, there is an increased risk of certain complications. Your medical practitioner will monitor your pregnancy progress closely, especially in the third trimester, to ensure proper growth and watch for warning signs like decreased fetal movement or abnormal heart rate. You may be required to have additional ultrasounds to check on your baby’s development and size.

While hearing may raise fears, a single artery umbilical cord is often detected by chance during routine ultrasounds and many parents go on to have normal, healthy pregnancies.

The risks can be managed well with close monitoring. Your baby’s health and safety are the top priorities, so don’t hesitate to ask questions if you notice any worrying changes.

Is A Single Artery Umbilical Cord Dangerous For My Baby?

Anytime you hear “abnormality” you’re likely to develop concern for the wellbeing of your baby. The good news, although an SUA is an abnormality, the majority of cases are isolated and not related to any dangerous conditions for you or baby.

Occasionally, a SUA can be related to other abnormalities in baby’s cardiovascular, renal or other systems, or related to a chromosomal issue. For this reason, your provider may recommend some further evaluations, but typically invasive testing isn’t recommended. A more detailed ultrasound to check for any other abnormalities and ongoing growth monitoring is a common course of action. If another abnormality is found, it might mean an increased risk of health concerns for your baby, but alone isn’t the cause for concern.

Some studies have found a slight increased risk of Intrauterine Growth Restriction (IUGR), while others have concluded the risk of IUGR among babies with SUA is the same as the general population. If your provider is concerned about IUGR, they will recommend routine growth monitoring. Some cases of IUGR are attributed to placental function and blood flow, and the presence of a SUA might be a risk factor. However, as mentioned above, there aren’t studies which confirm an increased risk so it’s something to be aware of but not something to expect to occur.

Potential Risks of SUA for Baby During Pregnancy

A single umbilical artery can put your baby at higher risk for certain complications during pregnancy and delivery.

One artery means less blood flow to the placenta, which provides oxygen and nutrients to your growing baby. This can potentially slow down growth and development in the womb.

There is also an increased chance of other problems, like blood pressure issues or blood sugar problems after birth. The majority of the time babies with SUA are born healthy without any long-term problems. However, some may require extra monitoring and testing after delivery to ensure normal development.

While an SUA can be cause for concern, with proactive management and care, many women go on to have normal pregnancies and healthy babies. Staying optimistic and following medical advice is the best way to take care of yourself and your baby.

Managing a SUA Pregnancy: Tips for Mothers

As an expectant mother with a single umbilical artery (SUA), the best way to have a healthy pregnancy is to take recommended precautions. Be sure to attend all scheduled appointments so doctors can check on your baby’s progress and watch for any potential complications.

1. Eat a balanced diet with plenty of nutrients like protein, iron, folate and omega-3 fatty acids to promote your baby’s growth. Staying hydrated and avoiding alcohol, drugs and cigarettes is also critical.
2. Get plenty of rest. Try to nap when possible and avoid stressful situations. Your body is working hard to support your baby’s development, so take the opportunity to put your feet up!
3. Pay attention to fetal movement and kick counts. Feeling your baby move around is a good indication that they are active and doing well.
4. Ask about possible signs of complications to monitor for, such as growth restriction or heart abnormalities. The earlier any issues are detected; the sooner treatment can begin.

Will SUA Affect Labour And Birth?

Many mother-baby pairs experiencing SUA can still have a low-risk, uncomplicated vaginal birth. Some studies, however, did find an increased risk of c-section due to small for gestational age (perhaps associated with IUGR) and fetal heart rate concerns showing signs of fetal distress.

One thing that is difficult to decipher with these increased risks is whether they’re due to the single artery umbilical cord or are they due to managing labor with SUA. If a baby is measuring small for gestational age or experiencing IUGR, a mother is more likely to be induced which increases the likelihood of fetal distress and c-section. With a single artery, it does seem that baby is at an increased risk of fetal distress and thus anything that also increases the risk of fetal distress (e.g. induction of labor, epidural, etc) could account for more c-sections or complications among babies with SUA due to combining risk factors.

As you and your maternity care provider monitor your pregnancy and plan for your labor and birth, it’s a good idea to discuss how to manage these risks. If there isn’t a medical indication for induction, augmentation, or epidural, it’s likely planning an unmedicated vaginal birth with fetal monitoring could be ideal.

Anytime you hear something that deviates from expected normal, especially during pregnancy, concerns can run wild. While hearing your baby has a single artery umbilical cord can be scary, the good news is that more often than not your baby will be healthy and your labor unaffected. In the few situations where other conditions are present or where labor doesn’t unfold as planned, discussing your options with your maternity care provider before labor can help you be prepared.