We congratulate Wilkins-Haug and colleagues for being able, by fetal cardiac intervention, to improve the postnatal quality of life and overall prognosis in five fetuses with severe aortic valve stenosis at risk for developing hypoplastic left heart syndrome1, 2. Yet, in our opinion, it should not be forgotten that there have been no substantial technical improvements in the percutaneous ultrasound-guided approach to fetal balloon valvuloplasty since its introduction more than one and a half decades ago. In a multicenter case series that we reported in 20003, technically successful percutaneous ultrasound-guided fetal balloon valvuloplasties without laparotomies were achieved in seven of eight fetuses with severe aortic valve stenosis, representing an even higher technical success rate than that reported by Wilkins-Haug et al.1, 2. (The four other fetuses described in our series3 had aortic atresia associated with closed foramen ovale (n = 2) and aortic stenosis and pulmonary atresia associated with hydrops (n = 2) resulting in additional technical and physiological burdens.) The low survival rate in the whole group of fetuses with severe aortic stenosis in our previous series3 reflects to a large extent the poor outcomes of postnatal management in infants with this lesion in the early 1990s; hence the improved outcomes with regard to survival in the experience of Wilkins-Haug et al.1, 2 seem to be a result mainly of the multiple advances in postnatal management since then rather than of any major technical break-through of the percutaneous ultrasound-guided valvuloplasty approach. Unfortunately, in the Boston series1, 2 as in our previously reported series3, percutaneous ultrasound-guided fetal aortic balloon valvuloplasty failed in most instances in achieving its goal, namely, a postnatal biventricular circulation. On an ‘intention to treat basis’, Wilkins-Haug et al.1 summarize that five of the 20 second-trimester fetuses with a high likelihood of developing hypoplastic left heart syndrome survived with a biventricular circulation. Expressed as a percentage, this result does not differ from the two of eight second-trimester fetuses that survived with a biventricular circulation in our previous series3. In our opinion, the main challenge, in order to increase the postnatal rate of functional biventricular circulation, remains to shift the intervention to far earlier in gestation. For this goal, the use of percutaneous ultrasound-guided fetal valve dilation seems limited. Wilkins-Haug et al.1 state that ‘imaging remains problematic’ (during fetal cardiac intervention) in their experience, ‘with three- and four-dimensional ultrasonography being explored’. Alternatively, we and others continue to develop fetoscopic and open interventional techniques that should allow fetal cardiac intervention prior to 20 weeks of gestation. The first of these techniques, fetoscopic transesophageal fetal echocardiography, has already become available in the clinical arena4. As expected from our studies on sheep, this novel imaging approach has kept its promise to significantly improve imaging and guidance during fetal cardiac intervention in humans. Just as, decades ago, cardiac surgeons had to tackle, and overcame, the formidable challenges of cardiac bypass, we fetal interventionists should not be deterred by the common occurrence of preterm premature rupture of membranes and preterm delivery following fetal surgery. The more recent clinical experience of our and other fetal surgery groups with both open and fetoscopic fetal surgical procedures already indicates that these risks can be reduced by experience and modifications in surgical set-up. Further advances can be expected if we succeed in obtaining sufficient industrial support to build much-needed interventional devices. T. Kohl*, U. Gembruch*, * Department of Obstetrics & Prenatal Medicine, German Center for Fetal Surgery & Minimally-Invasive Therapy, Sigmund Freud Str. 25, Bonn, North Rhine Westphalia, 23105, Germany