A single artery umbilical cord, known as SUA, is the most common malformation of the umbilical cord that is known today. By itself, having a single artery in the umbilical cord doesn’t pose much of a risk to the mother or the child. One artery is sufficient to support a pregnancy to its full term. Having SUA does, however, increases the chances of the child being born with certain birth defects.
Statistics on Single Umbilical Cord Arteries
1. Up to 67% of the children who are born when SUA has been discovered grow up to be healthy and free of any birth defects.
2. The two most common abnormalities that are seen with SUA are trisomy 13 or trisomy 18, which can affect intellectual development, heart defects, or small facial features.
3. The chances that a child born with trisomy 18 will survive past their first birthday: between 5-10%.
4. About 1 in 5 pregnancies with SUA will result in a slower growth of the fetus, causing low birth weights and early deliveries.
5. The chances that a pregnancy will become a miscarriage because of a single artery in the umbilical cord: 22%.
6. Having SUA causes a 6.7x increase of having some form of a congenital abnormality present during birth.
7. In a study of births over a 20 year period, only 1,600 pregnancies out of over 200,000 were found to have had SUA.
8. Cardiovascular abnormalities occur in 6.25% of confirmed SUA cases.
9. Having multiples increases the chances of having SUA for at least once of the children by up to 4x a single pregnancy. Every additional multiple increases the chances by an additional 4x.
10. The incidence of SUA is 0.25% to 1% of all single child pregnancies.
11. The rate of congenital anomalies in a pregnancy with SUA is 3x greater than in pregnancies without SUA present.
12. There is an incidence of SUA in 1.5% of miscarriages that happen spontaneously.
13. About 8% of the instances of SUA are missed on ultrasound readings and false negatives account for up to 40% of the misses that occur.
14. SUA affects between 1 in 100 and 1 in 500 pregnancies, or up to 1% of total pregnancies that are tracked every year.
Facts About Umbilical Cord
Normally the umbilical cord develops with three vessels. There are two arteries and then one vein. SUA occurs when just one artery develops instead of two. Why this happens is not entirely known, but it is thought that the original artery that develops in the umbilical cord simply fails to divide to create a second one during the initial stages of the pregnancy.
It is usually discovered on one of the first ultrasounds that are performed on an expecting mother. When it is found, the doctor or OB-GYN will likely require a mother to have more ultrasounds performed throughout the pregnancy in order to determine if any abnormalities are beginning to form. The good news is that if an ultrasound doesn’t pick up any issues, then there will normally be zero chromosonal or congenital abnormalities. As an added safety precaution, an echocardiogram might also be performed to ensure that a child is healthy.
Common Risk Factor
The most common risk factor for the development of SUA is becoming a mother at the age of 40 or higher. If a woman has had 3 or more children previously, there is some evidence that shows this also increases the risk of a single artery developing within the umbilical cord. Diabetes, either Type 1 or Type 2, also increases the chances of SUA occurring.
One of the most effective methods of treatment for SUA involves genetic counseling. When there is a history of heart problems within a family, then it is more likely for a heart abnormality to form with the fetus. When caught early and when family genetics are a factor, however, it is possible for a fetal surgery to repair the abnormality before birth.
Another factor in SUA is that it takes an extensive amount of ultrasound examinations in order to find the umbilical cord with a single artery. As the statistics show, many of the incidents aren’t discovered until after birth when the placenta or cord is sent to a lab for analysis. Most of the time this has no bearing on the pregnancy whatsoever since 3 out of 4 births have no abnormalities whatsoever with SUA.
If you have been diagnosed with a single artery in the umbilical cord, however, it is highly recommended that all fetal screening occurs so that a family can be prepared for whatever situation they may be facing. Although SUA is not necessarily an indicator of a birth defect on its own, there are several possibilities that a child may face. Edward’s Syndrome might be one of the worst-case scenarios, where the life of the child is greatly at risk, so discovering these abnormalities as soon as possible can help a mother weight all of her options.
It is also important to get echocardiograms of the fetus when SUA is suspected so that heart defects can be eliminated. This should become part of the regular check-up process and some mothers, especially those who are pregnant with multiples, may need to plan on weekly checks with their OB-GYN to track fetal development. It may be a lot of work and the costs of an SUA pregnancy may be much higher than one that is classified as “normal,” but outcome planning is necessary with this condition.
Expectant mothers should also be prepared for an early delivery. Many of the babies that are born with SUA tend to be born at least 3 weeks early. Knowing the signs of early labor, how to recognize contractions, and the methods of slowing down the process can lead to a more successful pregnancy. There might be higher risks with a single artery in the umbilical cord, but they are just risks. There’s an excellent chance that a happy, healthy child will be born.