Increased nuchal translucency and congenital heart defects in a low-risk population

Increased first-trimester nuchal translucency (NT) is a possible marker for congenital heart defects in euploid fetuses. In this study, we wanted to determine the sensitivity for congenital heart defects using the 95th centile of the NT as a cut-off point.

All women who booked for delivery in our hospital in the first trimester underwent NT measurement at a crown-rump length (CRL) of between 35 and 75 mm. In all euploid fetuses and newborns with isolated or associated CHD, NT was examined retrospectively and classified as normal (<95th centile according to CRL-dependent centiles in our own data) or increased (> or =95th centile).

From a total of 12,978 euploid fetuses screened, 27 had CHD (22 isolated and 5 cases associated with additional malformations). Moreover, 7 of the 27 fetuses also had increased NT (26%). Increased NT was significantly more frequent in fetuses with associated CHD (4/5) than in those with isolated CHD (3/22, Yates corrected chi2 p=0.012). In fact, the relative risk for CHD was 6.6 times higher in fetuses with increased NT compared to those with normal NT.

Increased NT for the detection of CHD performed less well than in other studies. Nevertheless, it can be used as an indication for fetal echocardiography.