Increased Nuchal Translucency and Pregnancy Outcome

To study the outcome of cases with nuchal translucency (NT) ≥ 95th centile in the first trimester of pregnancy. This cross sectional study was performed at Iranian Fetal Medicine Foundation (FMF) between January 2009 and December 2011. Totally, 186 cases with NT≥ 95th centile who attended for the first trimester screening were studied. All cases with increased NT including those with normal karyotype were followed up with anomaly scan at 18-22 weeks and fetal echocardiography at 22-24 weeks. Pregnancy outcome was extracted from delivery records and pediatrics notes and telephone interviews. Of screened cases, 186 fetuses had an NT≥95th centile, of them 19.8% were abnormal karyotype, including 29 cases of trisomy 21, three of trisomy 18, two of trisomy 13, three of Turner syndrome. 77.8% did not show any abnormalities on follow-up examinations. 4.6% of cases were found to have malformation antenatally and 4% cases postnatally. 11.4% women elected termination of pregnancy without further follow up. There were 4.6% fetal loss and 1.3% hydrops fetalis. In this unselected population, the study showed one out of four fetuses with enlarged NT had an adverse pregnancy outcome (miscarriage, fetal loss, and fetal abnormalities), however the chance of having a normal child after exclusion of chromosomal abnormalities and adverse pregnancy outcome was 95%.