You have already mentioned something like that. But let me ask this more specific question. You're specialized in treating unborn children and complicated pregnancies, as you mentioned. One particular complication is a pregnancy with two fetuses. And these two fetuses share a blood supply, but the blood flows are not even for each fetus. And therefore, this leads to overnutrition, oversupply of blood in one fetus, and undernutrition in another fetus. And as you mentioned, you are using endoscopic laser surgery to treat twin to twin blood transfusion syndrome. You are operating not on a fetus or a developing child but actually on a placenta. So, could you please more specifically outline how do you approach twin to twin blood transfusion syndrome? How do patients perhaps find you in these situations? You know, not everybody who has those conditions probably has the opportunity to come to an expert like you.
Nevertheless, I think it's important to so people are aware of how that is done, and so they can find an appropriate expert. Well, the surgery for a twin to twin transfusion now is reproducible in several centers. And I think that's what we could be proud of is to have designed a technique that is being used by different people with the same success. That's not something you start from the night before. But once you've done about 50 cases. If you apply the proper rationale to your strategy, entering the uterus is the most important. You expose correctly the operating field, then the surgery is not difficult because it's just a matter of coagulating vessels. There is no surgeon skill. It is just to enter the right place. So if you can do that, you're meticulous enough and exhaustive in searching for the abnormal vessels, then this surgery can be done in many places. Also, these women are affected by this syndrome. They cannot travel very easily. So there is a reputable center nearby, and there are now, in all developed countries, people who do endoscopic fetal surgery. It's better than traveling long distances because that's not comfortable for them to travel. So yeah, this fetal endoscopic surgery, the first one, was doing in 1991. So is it 30 years to have been able to assess its success and reproducibility. So I think it's a standard of care now. How are the outcomes? Usually, what is the expected clinical outcome for a twin to twin blood transfusion syndrome? What people could expect is 75% survival of both twins, 90% survival of at least one twin. So the risk is to lose one in about 15% and lose both in about 5%. Something like that. And if both twins survive, then the development is otherwise normal. It is completely normal.
Yeah, depending on at what gestation age they are delivered. But then the problem is prematurity. It is not twin-to-twin blood transfusion syndrome anymore. And is it common that prematurity affects the fetus after the surgery? Yeah, one of the Achilles heels of fetal surgery, endoscopic fetal surgery, and open fetal surgery (but again, we don't do it) is rupture of membranes because you have to go through those membranes with your instruments. So the membranes are fragile. Rupture of the membranes during the weeks following the surgery is very common. It is about 20%. Some of them ended up with preterm delivery. Some do not because it's only mechanical. So after that, not all women deliver very prematurely, but on average, women deliver at 33 weeks. In any case, we don't go further than 34 weeks because once you operated on the placenta, you've probably switched off part of the placenta in its function as well. And initially, years back, we've observed some late accidents like intrauterine death, or placenta abruption. And we thought that we could be more careful and deliver those babies a bit before. So on average, 34 to 35 weeks, we think it's the right time to deliver a baby after fetal surgery. But since then, you know, things even for normal twin pregnancies have moved on. It's well established now that twins should not be delivered later than 37 weeks. So if you deliver them at 35, after what they've been through with the syndrome, I don't think that's your problem.