Nuchal translucency and cystic hygroma colli in screening for fetal major congenital heart defects in a series of 12,910 euploid pregnancies.

OBJECTIVE

Many studies have shown that an increased nuchal translucency (NT) may be a good marker of fetal heart malformation, but the extent to which NT is suitable for identifying the population at risk remains unclear. We aimed to determine the value of NT measurement and of the presence of cystic hygroma colli in the screening of euploid fetuses for congenital heart defects (CHD).

METHODS

We carried out a retrospective analysis of 12 910 euploid pregnancies examined between January 1995 and August 2007 at our institution. The screening performance of NT measurements in identifying fetuses with CHD was assessed, with comparison between the use of cut-offs defined as absolute values, multiples of the median (MoM) and percentiles. The presence of cystic hygroma colli was also assessed in the prediction of CHD.

RESULTS

The incidence of major CHD was 3.4 per thousand (44/12 910). The sensitivity of NT measurement in screening for major CHD was 54.5% if the threshold was set at the 95(th) percentile, 45.4% if it was set at 3 mm, 27.3% for 3.5 mm, 50.0% for 1.5 MoM and 45.5% for 1.75 MoM. The false-positive rates for these thresholds were 8.4, 6.6, 1.7, 8.9 and 6.3%, respectively. The incidence of major CHD was 1.2% (10/813) in cases of thick NT (> 95(th) centile) and 4.3% (13/304) in cases of hygroma colli.

CONCLUSIONS

NT measurement during the first trimester is potentially useful for screening for fetal major CHD. Screening performance is consistent whether NT values are expressed as MoMs, percentiles or absolute values. The incidence of major CHD seems to be higher in cases of cystic hygroma colli.