> it's not possible for that to have gone unnoticed Keep in mind that 93% of heart defects are detectable via an echocardiogram around week 24 of pregnancy. So

> it's not possible for that to have gone unnoticed Keep in mind that 93% of heart defects are detectable via an echocardiogram around week 24 of pregnancy. So I would imagine that in most cases where the heart defect is fixable then it's repaired, or else if it's not fixable but also not serious then the kid is just prevented from doing sports. Or else if it's serious and not fixable then pregnancy is terminated. So I would expect the actual mortality to be substantially less than 2x. And given that heart-related mortality in children is extremely rare, I suspect it would be quite tricky to detect. Especially when you need to account for confounding issues like maternal age during pregnancy, ICSI use, etc. Given that there are around 5,000 CHD-related deaths in children per year, and around 1.5% of babies are IVF births, we're talking at most 150 deaths per year instead of 75, probably less due to the reasons mentioned above. And once you start trying to take into account imperfect data confounding variables, it's hard to say whether having definitive proof one way or the other is even within the realm of science at that point.