Pregnancy outcome and nuchal translucency measurements in fetuses with a normal karyotype

The aim of this study was to examine the relationship between nuchal translucency thickness and pregnancy and fetal outcome in fetuses with a normal karyotype and without structural malformations. Fetal nuchal translucency measurements were performed in 2088 chromosomally and structurally normal fetuses. In all fetuses the karyotype and pregnancy outcome were known. Likelihood ratios for different outcome measures were calculated. Spontaneous abortion, intra-uterine and neonatal death occurred in 2.4, 1.1 and 0.5 per cent respectively. The incidence of immature delivery was 1.1 per cent and of premature delivery 6.0 per cent. The only adverse pregnancy outcome recorded that was associated with increased nuchal translucency was spontaneous abortion. The likelihood ratio for the occurrence of a spontaneous abortion was 3.1 for measurements between 3.0 and 3.9 mm, and 6.8 for measurements>/=4 mm. Increased lethality in fetuses with enlarged nuchal translucency and normal chromosomes may provide evidence that the same insult causing excessive fluid collection in the nuchal region may also be responsible for fetal demise.