Objective: Increased fetal nuchal translucency is associated with increased risk for congenital heart defects. In the present study, we aimed to investigate whether fetal nuchal translucency distribution differs among different types of congenital heart defects and whether it can lead to an earlier diagnosis.
Study design: Four fetal echocardiography units provided data on fetuses with a congenital heart defect diagnosis in whom nuchal translucency thickness had been measured in the first trimester. Nuchal translucency data were compared per chromosomal status and type of congenital heart defect. Data on gestational age at diagnosis were also analyzed.
Results: Six hundred thirty-seven cases of congenital heart defect with known karyotype and exact nuchal translucency measurements were analyzed. Nuchal translucency was > or =3.5 mm in 22.9% of chromosomally normal fetuses (n = 397) and 58.8% of chromosomally abnormal cases (n = 240). Among fetuses with normal karyotype, the proportion of cases of congenital heart defect with increased nuchal translucency was similar in each of the subtypes of congenital heart defect (P = .96). Mean gestational age at diagnosis of congenital heart defect in fetuses with normal karyotype was 22.1 weeks with nuchal translucency of <3.5 mm and 16.1 weeks with nuchal translucency of > or =3.5 mm.
Conclusion: Finding nuchal translucency of > or =3.5 mm may lead to an earlier diagnosis of all major types of congenital heart defects.