[Increased fetal nuchal translucency thickness and normal karyotype: prenatal and postnatal follow-up]

The aim of this study was to evaluate pregnancy and postnatal outcomes of fetuses with increased nuchal translucency thickness (NT) and normal karyotype.

Two hundred seventy five fetuses with increased NT were examined with karyotyping analysis, serial ultrasound scans, echocardiography and postnatal clinical and genetic evaluation at the Fetal Medicine Unit - Department of Obstetrics - São Paulo University.

The karyotype was abnormal in 14.2% of the cases and normal in 85.8%. In cases with normal karyotype 24.7% presented structural abnormalities at the anomaly scan, one third of these were major malformations with 35.7% of heart defects. Adverse pregnancy outcome such as miscarriages, intrauterine and neonatal deaths occurred in 10.2% of cases. Of the infants 72.7% had postnatal examination, with 14.8% presenting abnormalities. Chances of having a live and healthy child decreased with increased NT thickness, and were of 37.5% for NT above 4.5mm.

In cases with increased NT thickness and normal karyotype, the frequency of fetal malformations, especially heart defects, adverse pregnancy outcome and postnatal abnormalities is related to the NT thickness.