Pregnancy outcome in fetuses with increased nuchal translucency thickness at 10-14 weeks of pregnancy

Increased thickness of fetal nuchal translucency (TNT) measured at 10-14 weeks of gestation, may suggest underlying fetal chromosomal defects, structural abnormalities or genetic syndromes. We examined the relationship between increased TNT and pregnancy outcome, especially in fetuses with normal karyotypes. 1400 pregnant women underwent first trimester scanning and screening for chromosomal abnormalities and measurement of fetal TNT. 25 fetuses (2%) with increased TNT (> 3 mm) were identified. 8 (30%) had an abnormal karyotype. Of these, 5 pregnancies were aborted, 3 ended in spontaneous abortions before karyotyping, and 2 were terminated, all before detailed cardiac scanning. There was a high association between increased TNT and karyotype abnormalities. The total incidence of favorable outcome in fetuses with normal chromosomal and cardiac features but enlarged TNT was 56%.