Our Single Umbilical Artery (SUA) Pregnancy Experience

single umbilical artery

Image of single umbilical artery from myhealth.alberta.ca

There was really no point in my pregnancy that I was not afraid I was going to lose the baby. In part, that fear stemmed from the emotional rollercoaster that pregnancy after loss can be under the best circumstances. And, in part, it arose from finding out that the baby and I had a single umbilical artery.

We found out about the SUA at our 20 week anomaly scan, and the doctors were moderately reassuring. I am a researcher by training, however, and when I went in search of more information on my own, what I found was just frightening. And I couldn’t find any stories from families—just a bunch of medical journal articles that kept me up at night with visions of stillbirth. So, I wanted to share our story to put something a little more personal out there, in case you find yourself in this situation. DISCLAIMER: please do not take this as medical advice. I’m not that kind of doctor. This is just our family’s story.

What is a single umbilical artery?

I had never heard of it before, but a single umbilical artery affects an estimated 1 in 100 pregnancies. Not that rare, really. Basically, a typical umbilical cord is made up of one big vessel and two arteries. One of the midwives told me that it looks like a smiley face. The vessel is what brings the blood, oxygen, and nutrients to the baby. The arteries are what carry waste away from the baby. In theory, having just one of those arteries does not have to affect the baby whatsoever. At least 75% of these babies come out just fine and you’d never know that there was a SUA unless it was found on the ultrasound or until cutting the cord. A lot of doctors don’t even check for it.

When paired with other anomalies, however, a SUA can be a soft marker for chromosomal abnormalities. On our 20-week scan, they also saw a “bright spot” on our daughter’s heart. I knew something was up, because the sonographer, who isn’t allowed to really say anything, asked twice if I’d had a Quad Screen done. Again, on its own, that bright spot means nothing, but with the two put together… The doctor (a specialist, not my usual provider) told me that with those two markers and my age (ahem, I am only 33, thank you very much), he’d put the chance of Down Syndrome at about 1 in 300 and he recommended that we do genetic testing.

By the way, because of COVID-19 restrictions, my husband was not in the room for any of that. We video called him in for the gender reveal, but after we hung up is when I got all the complicated news. I had some blood drawn for the testing and then went to the lobby to meet him and fill him in.

The five days between when we had our appointment and when we got the results of the genetic testing back were agonizing. I made the mistake of Googling some of the chromosomal abnormalities that the test checked for and several of them were fatal. We breathed a huge sigh of relief when the testing came back negative. Although there was still a chance of complications, particularly in the baby’s heart or kidneys, we were at least 99% sure that we were not looking at something major.

Still, however, I had a hard time not worrying about potential complications. Not everything can be diagnosed from an ultrasound. And in the literature on SUA, increased risk of stillbirth came up over and over. I tried not to worry too much, committing myself instead to praying that our girl would come to us healthy.

Are we having Intrauterine Growth Restriction (IUGR)?

Our next in-person appointment was a growth ultrasound at 28 weeks. This was the last time Julio was allowed to come to a prenatal appointment, and even then they only let him come because I just showed up with him, not realizing that the policy at my OB’s office had changed. Because the SUA can lead to Intra-Uterine Growth Restriction and related issues, our baby was getting a little extra monitoring, thus the ultrasound. Although her legs were pretty long and that put her in the 35th percentile overall, her head and belly were measuring just under the 5th percentile. Tiny. IUGR is typically diagnosed when the measurements fall under the 5th percentile. The midwife who met with us to go over the results decided to refer us back to the specialists for another growth ultrasound in two weeks, explaining that their equipment was better and she wanted to be sure that this slowdown in growth was not due to a difference in equipment or technique between the two offices.

It was really hard not to feel like I was failing. It had taken us so long to make this baby and now she wasn’t growing. The midwife told me, more than once, that there was nothing that I was doing or not doing that was causing the SUA or the dropoff in growth. She reminded me that the umbilical cord forms based on DNA that I can’t control. I asked if I needed to eat more—I was already focusing so much on eating nutrient-dense food every couple of hours. She said that giving the placenta good nutrition couldn’t hurt, but how the nutrients were delivered to the baby also was not something I could control. It just was what it was. I personally, do not connect with the phrase “it is what it is.” I ate more anyway. Grow, baby, grow.

At 30 weeks, we headed back to the specialists for another growth ultrasound. The sonographer really took her time to get good measurements, confirming with the doctor that she had done one of them correctly (the baby was not positioned super conveniently), which I really appreciated. The doc talked to me about the results of our genetic testing and looked at the ultrasound. The baby was still small, but her head and belly measurements were up over 10% and her interval growth looked good, so he referred me back downstairs to my primary practice, saying that they should refer me back upstairs if anything changed, but for now he thought we were okay.

“Oh, he’s the guy up there,” the midwife told me when she looked at the report from our ultrasound. That gave me a lot of comfort. So, the plan was to just keep monitoring the baby closely.

Weekly Fetal Non-stress Tests (NST)


A fetal non-stress test

Starting at 32 weeks, I had weekly visits for a fetal non-stress test, which basically is a non-invasive way to monitor the health of the baby and that she is getting enough oxygen. I wore two sensors, one that picked up the baby’s heart rate and another that picked up movement by or in the uterus. The test result is either reactive or non-reactive. A good, reactive result shows that when a baby moves, their heart rate picks up and then comes back to their baseline. Our daughter passed these every time and I actually really enjoyed listening to her heartbeat for 20-40 minutes every week.

At 36 weeks, we had another growth ultrasound and, although the dopplers on the umbilical cord looked good and our girl was growing, her growth had dropped off and her belly was back down to the 4th percentile. Typically, when growth slows, the belly is the first place to taper off. Her head was just over the 5th percentile. One of the doctors at the practice we go to advised the midwife that we should consider inducing at 39 weeks to “quit while we’re ahead,” rather than risk the placenta not doing its job. Another ultrasound was scheduled for 38 weeks, with the plan to discuss the week 39 induction further then.

Honestly, talk of an induction took birth from something that I had no fear or anxiety about to something that I was quite anxious about. I felt strongly drawn toward unmedicated, low-intervention birth and I knew that, while inductions can be no big deal, they can also lead to long, very painful delivery and increase the odds of having a cesarean birth. At 37 weeks, I discussed these concerns with the midwife and she and I went over some things I could do to encourage spontaneous labor at home, in hopes that I could get baby to come on her own before an induction. She was already sitting pretty low, so I felt hopeful and reassured.

At 38 weeks, the growth ultrasound showed that, while baby girl was holding onto the 24th percentile, with a small head and belly, but legs in the 88th percentile, her interval growth was still coming along. She was not growth restricted, but she was probably going to be small. The NST showed a very active baby. So, the decision was made not to schedule the induction and keep trying for spontaneous labor. I was told, though, that for me “the margin for anything weird is low” and I should call the midwives if anything changed at all. The baby had also turned face down and was riding even lower. Yay.

What Happened?

The doctors wanted the baby born by 40 weeks, but my midwife thought that she was doing well and we could try to get her to 40 weeks. The compromise was that we scheduled an induction on my due date. I was told that while births for kids with SUAs can go smoothly, they can also get a little weird. I tried everything to get labor going. I walked so much that I hurt my hip. But, baby girl was staying put. Maybe it’s because I watched the news every night during my pregnancy and she had heard too much about 2020 to want to come out. I don’t know, but I went in for a COVID-19 test two days before our due date, and we reported for the induction on our due date with this mama feeling some combination of resigned to it and at peace with it.

We took the induction the slowest, gentlest possible route so that if the baby was not tolerating any of the methods, we could stop or slow down. A day and a half later, our daughter was born! Her APGAR scores were high, she nursed right away, and there are no signs of any complications related to that pesky umbilical artery. And that little head that had everyone worried? At birth, her head was at exactly the 50th percentile and she was well over six pounds. She’s pretty cute, too.


I am so grateful that our girl moved a lot throughout the pregnancy, so I had continuous reminders that she was okay. I am also so thankful for the support of our midwife and the doctors who monitored our baby, but also took a holistic view of her health and mine—even after the induction, I still got the unmedicated, intervention-free delivery that I wanted, once labor started. I am grateful for the prayers of friends and family and that we have good insurance and that I had sick time for all those appointments. Most of all, I am grateful that we have a healthy daughter sleeping on me as I finish writing this.

After delivery, my midwife showed the umbilical cord to the nurses and sent the placenta off to be analyzed, as is standard practice when there is an abnormality with it or the cord. The baby nurse present for our delivery told Julio that his 18 month-old daughter had a SUA and was doing great. “Watch out for those single umbilical artery girls; they’re feisty,” he said.

If you have a SUA, I know that what is out there on the internet can be really scary, but in most cases your baby will be okay. Listen to your doctors, but also take some deep breaths and stay off of Google.

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