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This is a transcription of a portion of a Healthful Woman podcast.

Katie’s Question

Our first question in this episode was from Katie:

“I’m 29 weeks pregnant. And at my 20-week ultrasound, it was discovered that my baby has a duplicated collecting system and a ureterocele on the right side. The right upper pole of the kidney is severely dilated, and in my most recent follow-up ultrasound, it was looking as though the left kidney is starting to show some mild dilation as well. My husband and I are obviously very concerned and anxiously waiting next steps and follow-up ultrasounds, but I wondered if you were aware of any intrauterine treatment options for decompression of the ureterocele. My maternal fetal medicine doctor said she would look into it, but that would likely all be investigational, which is what I found so far as well. I would really appreciate any insight you have into this, even if it’s just to confirm that no treatment options exist until after the baby’s born. Of note so far, the amniotic fluid level is normal.”

Dr. Fox’s Response

All right, Katie, that’s a good question. It requires some background. So, for our listeners, all of us, ideally adults, children, and fetuses have two kidneys. They’re located in the back side of our abdomen, so sort of closer to your back than to your front, a little bit high up, sort of just under your ribs in the back. What the kidneys do, again, this is true in adults, children, and fetuses, is the kidneys filter our blood, and they take out some stuff like some toxins or salts or whatever it is, and they produce urine, pee, which first collects inside the kidney, in the middle of the kidney, and then that urine drains out of these little tubes that exit the kidney, one on each side, called the ureter that goes to the bladder, right? And then at some point after the bladder fills, you pee, and all that urine comes out. Okay, so that’s what normally happens.

Now, when we do ultrasounds in pregnancy and we’re looking at the baby, starting at around 16-plus weeks, we usually take a look at the kidneys. And what we typically see, right, we see two kidneys, one on each side, and usually what we’ll see is that there’s sort of like spongy tissue on the outside, and in the middle, we’ll see a little collection of fluid, which is supposed to be there. That’s the urine they’re collecting. We do not normally see the ureters, those tubes that drain the kidneys, because they’re very, very thin and usually collapse, so we don’t usually see them on ultrasound. We know they’re there. We won’t see them. And then we usually will see the bladder with some amount of urine in it. And then what we see on ultrasound is the amniotic fluid, which is the fluid outside the baby, which, after 16 weeks, is predominantly baby pee, fetal urine. So, all of those things we look at to evaluate the urinary system in fetuses, and obviously in most babies, everything’s perfectly fine, but some things are not so fine.

Now, when looking at the kidneys, it is very common that in one or both kidneys, we’ll see a little bit of extra fluid, and we call that sometimes pyelectasis. We sometimes call that urinary tract dilation or UTD for short. That is a common finding. It usually means nothing for the baby, nothing for you, nothing to do about it in pregnancy. It usually goes away either during pregnancy or after delivery, and the reason it’s normally there is the babies, they’re small, they’re kind of smushed inside there, and so those ureters, those tubes that drain the kidneys, since they’re very thin and very fine, they could get kinked or twisted or compressed, and there’s a little bit of backup of fluid. Think of it as plumbing. And as the baby gets bigger, those tubes open, the kidneys drain completely, and everything is fine. So, that finding is rarely concerning and typically does not need anything done during pregnancy or after delivery, meaning not while you’re pregnant to the fetus, not after delivery to the baby; everyone’s typically fine.

Now, some circumstances are a little bit more advanced than that, where we think there’s actual blockage, like obstruction of something in that system. So, Katie, what you described is, number one, that the baby has a duplicated collecting system. So, a duplicated collecting system means that on one of the kidneys, instead of one ureter, one tube comes out of the kidney, two tubes are coming out of the kidney, so that doesn’t sound so bad, but when fetuses have that, usually or often, one of those two ureters is not functional and is blocked. And so one of them works and the other one is blocked, so the one that’s blocked will just back up. And since that one backs up, you end up getting sometimes a dilated ureter, right? You do see the ureter in this case because it starts filling up, and you can get back up into the kidney, and you can get something called a ureterocele, which is where it sort of outpouches into the bladder, and you can sort of see it pouching into the bladder.

So, all those things, that’s one sort of abnormality that you could have that’s a little bit more…. I say the word severe, but I don’t mean that unhealthy, that something’s going to hurt the baby, but just severe in that we see it, it looks more prominent, more significant. Those types of abnormalities typically do need to be corrected after birth surgically, right? So, a pediatric urologist who’s a urologist for children will typically have to correct that with some sort of procedure, some sort of operation. Fortunately, those babies tend to be perfectly healthy. They recover fine, and typically they go on in life with two working kidneys, and everything is good. So, when someone’s pregnant and we see anything going on with the kidney, the first thing we try to differentiate is whether this is one of those things that pretty much is going to be fine, going to go away either while you’re pregnant or after birth, or is this one of those things that we predict the baby will need surgery for. Now we’re not always right. We could be wrong. It was just a prediction.

Now, your question was, okay, so you see one of these things that we think or predict is going to need surgery after birth. Is there something we can do during pregnancy to either fix it or make it better? And the short answer is, no, there isn’t anything that we could do that is safe or that we would want to do because it is not common that one of these things would actually harm the baby inside, either the baby in general or the kidney. And so anything that you would have to do to “fix it” would basically be pretty invasive, right? You have to go in through the uterus into the baby to do something, or drain, and even if you drain something, it’s going to fill up again. You’d have to actually surgically do something to the baby, and that’s a pretty advanced and high-risk procedure to fix something that doesn’t really need to be fixed, typically, while you’re pregnant. It needs to be fixed after birth, right?

The times when you do fetal surgery are usually situations where it’s either very dangerous to the baby during pregnancy, and the only option is to fix it during pregnancy, or if it’s known that if you take the risk and fix it during pregnancy, the outcome after birth is better than if you wait till after birth. So, one of the classic examples of that is in many cases of spina bifida, there’s data that, if you do fetal surgery and correct it during pregnancy, those babies tend to do better than if you wait till after birth. That’s not uniformly true, but whatever, that’s a condition where it’s on the table. It’s a possibility. But for kidney conditions, typically no, because the risk of the procedure would far outweigh any benefits. And again, these babies, typically, the main decision we’re trying to figure out is, “Will the baby need surgery or not?” It’s ultimately decided after birth, but we could help predict it. But what I like to remind people is that even if your baby needs surgery, they are typically perfectly healthy and grow up without any issues afterwards. Obviously, as a parent, you’d prefer your child not to need surgery, but in those circumstances, they do tend to do well. Good luck.

Learn More on the Healthful Woman Podcast

Dr. Fox answers several other questions about epidurals, long-distance providers, and abdominal pain during pregnancy. To learn more, check out the full podcast episode.

Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!

Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!