I went in for another ultrasound, a 2-week follow-up to my comprehensive, last Friday. After speaking with the maternal-fetal specialist, I am even more confident now that the most likely problem is NOT a chromosomal defect, but an isolated kidney issue. The choroid plexus cysts have almost entirely dissipated (in just two weeks!), and she said that if a chromosomal defect pattern were to show up on ultrasound, it almost certainly would have made its presence known by now. The dilation remains the same (both kidneys are affected, and the size of the dilation is quite significant), but baby's growth and the amniotic fluid levels were fine, which means that kidney function does not appear to have been affected at present.
This is a huge relief!
After sharing the news with friends and family two weeks ago, I have had at least 4 people e-mail me to tell me that their child had a similar kidney problem before birth. None of their children required surgery after birth, none of them had to deliver early, and only one parent continued with monitoring for just the first year or two of their son's life. It was simply an unusual pattern of normal in utero development.
This is also a huge relief!
My mother, who is an emergency room physician, did some research on hydronephrosis and found that it is one of the most common abnormalities detected on prenatal ultrasound, even in low-risk women ("Hydronephrosis is the most common pathologic finding in the urinary tract on prenatal screening by ultrasonography, accounting for 50% of all abnormal findings"). Very frequently, the baby outgrows the problem before birth ("In more than half of the cases where hydronephrosis shows up on ultrasound, it resolves itself by the time the baby is born or soon after"). In all of the cases where hydronephrosis caused a problem with the pregnancy or the immediate postpartum period, oligohydramnios (low amniotic fluid) was detected ("In the presence of a bilateral obstructive process, oligohydramnios is the best predictor of an adverse outcome").
This is yet another huge relief!
I have some concerns about the way the problem is being monitored and, therefore, the way recommendations are being made about the care and treatment. Both my pediatrician sister and my mother seemed to think that oligohydramnios was the most important thing to monitor for, but I actually had to remind the doctor to check the amniotic fluid. When I asked the maternal-fetal specialist how she would know whether there was a problem, she said she was looking at "kidney function." I questioned her about how she knew whether the kidneys were functioning, and she said it was by looking at the structure of the kidney - how compressed it was as a result of the dilation. But that didn't seem right to me. I'm sure that more compressed kidney is more likely to impair kidney function, but isn't amniotic fluid the best way to measure whether the baby's kidneys are actually functioning? I mean, since amniotic fluid is basically just baby urine. She was somewhat equivocal about that. She said she didn't think early delivery would be recommended, because we would want to keep the baby in as long as possible to give him a better chance to develop properly. I repeated the question about the amniotic fluid. If it begins to drop rapidly, might it not be a good idea to get him out so we can correct the problem? I didn't mean right now: I know that the baby couldn't survive outside me now. But say, if the problem develops later in the third trimester? I guess I thought there might be surgery they can do on the outside to fix it that would be impossible or more difficult in utero. But she kept stressing kidney function (by which she meant the compression of the kidney), rather than amniotic fluid.
So, I'm a little bit confused. I also asked her whether they might be able to locate the obstruction - or whatever it was that was causing the fluid to be retained in the kidneys and dilate them - and it didn't really seem like that was possible, either. I thought perhaps she'd be able to see it as the baby grew older, but she was pretty non-committal.
Giving her the benefit of the doubt, it's possible that she wasn't thinking long-term, and was only giving me answers about what she was seeing on the current ultrasound. And of course, she would recommend waiting as long as possible if I'm only at 21 weeks now. It was of some concern to me, however, that she didn't look for the amniotic fluid levels until after I mentioned it. If she didn't think the amniotic fluid would be an issue, and she wasn't going to ever be able to locate the obstruction, and she thought keeping the baby in as long as possible was the best answer, why am I coming in for ultrasounds all the time? There's a lot I don't understand about the long-term prognosis and course of treatment here. I may just try to schedule a consult with a pediatric urologist to find out more. Or maybe I need to give her another phone call.
It was also somewhat irksome that she kept saying that my baby probably has a kidney defect because I'm a Type I diabetic. She never once mentioned how common this problem is, nor the fact that it frequently resolves before birth ("Antenatal hydronephrosis without associated urinary tract anomaly is the etiology in the vast majority of infants with hydronephrosis (79-84%) and has been termed isolated antenatal hydronephrosis (IAHN)"). I'm not saying it's definitely not because I'm a diabetic; I just don't think it's a foregone conclusion.