Early diagnosis of major cardiac defects in chromosomally normal fetuses with increased nuchal translucency

Objective To determine the value of early ultrasound examination for prenat al diagnosis of cardiac defects in chromosomally normal fetuses with increa sed nuchal translucency thickness at 10-14 weeks of gestation. Design Prospective audit. Setting Fetal Medicine Centre. Methods Specialist fetal echocardiography was carried out in 398 chromosoma lly normal fetuses with a nuchal translucency measurement above the 99th ce ntile (greater than or equal to 3.5 mm). In the first 75 pregnancies the ca rdiac scan was carried out at 17-22 weeks and the next 323 cases had one sc an at 13-17 weeks and another at 20-22 weeks. Pregnancy outcome was obtaine d in all of the cases. Results Major cardiac defects were present in 29 (7.3% of 398) cases and in 28 of these the diagnosis was made by antenatal echocardiography. In 27 of the 29 fetuses with major cardiac defects echocardiography was carried out at 13-17 weeks and an abnormality was suspected in 24 of the cases (88%). Conclusions Increased nuchal translucency in chromosomally normal fetuses i s associated with an increased prevalence of major cardiac defects and, as such, is an indication for specialist fetal echocardiography. Most of the c ardiac abnormalities are detectable on antenatal fetal echocardiography and many can be excluded by early scanning.