Objective: To investigate different cut-off levels of nuchal translucency (NT) to predict abnormal cardiac findings (ACF) in second trimester ultrasound examination and confirmed postnatal congenital heart defects (CHD) in euploid pregnancies.
Methods: A retrospective analysis was performed on singleton pregnancies examined in our ultrasound units from 2006 to 2011. Fetuses with an abnormal karyotype were excluded. Different cut-off levels of NT thickness were analyzed to evaluate its performance to detect the ACF on second trimester ultrasound (2nd US) examination and also the CHD detected in neonatal follow-up evaluation of ACF cases.
Results: Of the 12,840 cases, a total number of 8541 euploid pregnancies were included in the study. Thirty-three had ACFs detected by 2nd US (3.86/1000). The mean NT thickness was found to be higher in fetuses with ACFs (p < 0.0001). Of 33 ACFs, 17 (52%, 1.99/1000) had major CHDs in neonatal follow-up. The area under the ROC curves for NT thickness to predict ACFs and CHDs were 0.67 and 0.65, respectively.
Conclusions: Higher NT thickness is associated with higher risk of ACF. NT is a weak predictor of ACF and major CHD; however, fetuses with an unexplained increase in NT measurement should be referred for further cardiac investigations.