When the umbilical cord and placenta are different
Julie wrote with a special concern. She went to her 20-week ultrasound and got some worrisome news: her umbilical cord only has two vessels. Her placenta is very close to her cervix and her doctor said it had a "lip." Since Julie's writing me for information, it makes me wonder just how much her doctor explained when he dropped a worry-bomb on her.
First let's talk about that umbilical cord. Most cords have one vein and two arteries. The vein carries oxygenated blood from the placenta to the baby and the arteries carry deoxygenated blood from the baby to the placenta. In approximately 1% of pregnancies there are only two vessels —usually one vein and one artery. In about 75% of those cases, the baby is entirely normal and healthy and the missing artery isn't missed at all. It's that other 25% that causes so much worry. Sometimes a 2-vessel cord is a sign that the baby has other abnormalities—sometimes life threatening and sometimes not. Hopefully, the rest of Julie's ultrasound reassured her that the baby didn't have any other glaring problems and she can assume she's in the good 75%.
But what if she's not. Oh, Julie, I know mothers. No matter what positive things the doctor may have said about the whole rest of your ultrasound, the news about the cord is uppermost in your mind. I don't blame you. I've written before about the dismissive "don't worry." Yeah, right. Of course you'll worry. You're a Mama. That's what we do.
If your baby is in the 25% where the 2-vessel cord is an indicator of other problems, you need more information. Your doctor will most likely refer you to a perinatolgist, an obstetrician who specializes in high-risk pregnancies. You'll have more ultrasounds and if you decide you want it, genetic testing. Depending on what information you receive, you will either be reassured that all's well or you'll find out more specifically what type of challenges your baby will have. Then there will be more decisions to make. Some parents, when faced with a potentially "different" baby decide to do nothing. They figure they'll take it as it comes, meet this baby when he's born and deal with whatever happens. Others get all the info they can up front, do research, find resources and prepare themselves in advance. Still others, and this is a minority, decide they don't have the resources to raise a child with serious anomalies and terminate the pregnancy. No matter which avenue they take, this is a tough, tough, time for parents who must give up the dream of having a "perfect" baby.
Let's get back to the other 75%—the one where the baby is just fine. There might be extra ultrasounds and checkups in your pregnancy to watch for intrauterine growth retardation. That's medical-speak for a baby who doesn't grow as big as we'd like in the uterus. That pesky 2-vessel cord is obviously attached to the placenta and if baby's not getting adequate oxygen and nutrition through it, baby might not grow well. What do we do then? We keep a close eye on baby and deliver him/her as soon as we can ascertain he/she's old enough to grow better outside the uterus than inside. This baby might end up in a special-care nursery or might just get out into her mother's arms, breastfeed like a fiend and grow beautifully. That's a wait and see situation.
Now, about that placenta. Frankly, I'm not sure what your doctor meant by a "lip"—if he said the placenta was close to but not covering the cervix. I can, however, talk a little bit about what it means when the placenta is too close to the cervix. That placenta is baby's best friend, source of blood supply, oxygen, food, everything. We need it to be safe, healthy and to hang on for the whole pregnancy. If it's covering the cervix, that's called a placenta previa. Babies can't be delivered through a placenta-covered cervix because it will destroy the placenta leaving mother and baby at risk for hemorrhage. It has to stay in good working order all the way through delivery. Once baby's born, fine—retire, already. Just not one moment sooner.
Most of the time however, as the lower uterine segment grows, it outpaces the placenta, essentially moving the cervix away from it. Once the placenta is clear of the cervix, there's no longer any danger. If it doesn't move out of the way—that's a darn good reason to have a cesarean section. There's no other way to safely deliver the baby. You're also looking at bed rest through the third trimester to decrease chances of bleeding.
Julie, I'll bet, when your doctor said there was a placental "lip" he was talking about a marginal placental previa. Most of those resolve into normal placental placement by the third trimester—meaning, the placenta gets out of the cervix's way and you don't have a problem. But for now, I'll bet you're worried, scared and maybe a little annoyed if your doctor hasn't given you some direction as to what the heck all this means. Honey, you need more information. Unfortunately, you may just have to wait and see what happens with the placenta over the next couple months. The 2-vessel cord, though? Tell your doctor you want to see a perinatologist and find out more. I'd love to hear what comes of this. I'm going to hope that your little one is fine, perfectly healthy (like most 2-vessel babies are) and this will be the last of your worries. That is until he or she's a teenager. This parenting thing's tricky right from the start, isn't it?
Got a question for Jeanne? E-mail it to firstname.lastname@example.org and it may be answered in a future blog post.
This Fit Pregnancy blog is intended for educational purposes only. It is not intended to replace medical advice from your physician. Before initiating any exercise program, diet or treatment provided by Fit Pregnancy, you should seek medical advice from your primary caregiver.