Fetal Renal Impairments in PUV

So when we look at what happens during pregnancy when a child is diagnosed with post fetal valves, we know that the source of the fluid around the baby, the amniotic fluid starting around 16 weeks of pregnancy throughout the remain of the pregnancy, is the baby's urinary tract. The baby's kidneys are making very, very dilute urine that the baby then pees out, and that replenishes the amniotic fluid. The baby's also constantly swallowing it, so there's a significant turnover of this fluid. And when we don't have enough fluid around the baby, then there's not that positive pressure on the baby's lungs to keep the fluid that is required for the lungs to develop properly, so they will develop what we call hypoplasia underdevelopment of the lungs. There's uh ongoing damage to the bladder and the ureters. The ureters are the tubes that connect the kidney to the bladder. There's ongoing injury to the kidney. Early on, some of this is reversible if we're able to make the diagnosis early in the pregnancy and consider a fetal intervention, which we do here at Cincinnati through our fetal care program. We might be able to stop that injury and hopefully reverse it. Um, when there is a significant lack of amniotic fluid, the long bones are deformed, and sometimes there can be in utero during the pregnancy, loss of the pregnancy. Most often though, these babies are carried to term and are delivered, but then if their lungs aren't healthy, they'll, they won't survive beyond the first couple of days. The lack of fluid does increase the risk of prematurity of the uh pregnancy and the babies might be delivered too soon. We also know that any time we intervene during the pregnancy that it does increase the risk of prematurity. And then there's the maternal complications that might arise from some of the interventions that we undertake. So there is a pretty significant involvement throughout the entire baby's body and also um injury to the mother when we have a pregnancy that's complicated by significant posturethral valves in the baby. And the the reason why the babies will sometimes have renal injury that progresses to complete loss of kidney function is either the kidneys are so malformed early during the developmental process that there's no functional kidney during the pregnancy, and then there's no fluid around the baby, and that's a pretty significant insult to the baby's development. Um, you can have dysplasia even without post fetal valves. It just means that the kidneys didn't form correctly for a variety of different reasons, of which post fetal valves is one of them. There can also be secondary damage to the kidney after birth. Um, there can be ongoing injury to the kidneys from infections, from high blood pressure, from high pressure in the bladder, from reflux where urine backs up from the bladder into the kidneys, and, um, down the road when the kidneys aren't working well, then they can make the bladder dysfunction even more significant. So the bladder doesn't empty well and then that causes a kind of a vicious cycle where that injury then propagates in the kidneys and the kidneys get more damaged. They make the bladder more damaged and it just keeps going back and forth. The key to understand that when we transplant a child, if we don't address the bladder, then the same fate that befell the the baby's own kidneys is going to happen to the transplant kidney too. So we're very, very careful and very deliberate in our understanding of what's going on with the baby's bladder and how do we keep the baby safe.