Objective: A prospective study of pregnancy outcome in fetuses with increased nuchal translucency above the 95th centile (group NT) or cystic hygroma (group CH) at 10 to 14 weeks of gestation was performed.
Patients and methods: Maternal and fetal data (nuchal translucency, caryotype, pregnancy outcome) and infant follow-up of 223 fetuses with first trimester nuchal translucency thickness (183 NT and 40 CH) were analysed.
Results: The measurement of nuchal translucency thickness shows a significant difference between group CH and NT (7.4+/-2.9 mm compared 3.7+/-0.8 mm). Chromosomal abnormalities were present in 55% (22/40) in group CH, with 9 cases/22 (40.9%) of Turner syndrome, compared with 14.2% (26/183) in group NT with trisomy 21 in 15 cases/26 (57.7%) (P<0.05). The rate of unfavourable outcome of pregnancy (spontaneous abortion, elective termination of pregnancy, serious structural anomalies) was 80% (32/40) in group CH compared with 18% (33/183) in group NT (P<0.05). In chromosomally normal pregnancies, the rate of fetus with no visible serious structural anomalies was 44.4% (8/18) in group CH compared with 93% (146/157) in group NT (P<0.05).
Discussion and conclusion: Our data show ultrasonographic evaluation of the fetal nuchal translucency thickness at the first trimester is actually indispensable. Neonatal outcome and malformation rate in fetuses with increased nuchal translucency or cystic hygroma are different, even with normal karyotype.