High-resolution real-time ultrasonography now permits the differentiation between nuchal translucencies and cystic hygromata of the neck in the first trimester. A series of 85 nuchal anomalies are presented that were diagnosed by ultrasonography at 9-14 weeks' gestation; their association with chromosomal defects and fetal outcome are also presented. Chromosomal anomalies were found in 8/29 nuchal translucencies and in 16/56 cystic hygromata of the neck. However, in fetuses with normal karyotype, additional defects were diagnosed in l0/40 fetuses with cystic hygromata and in none with nuchal translucency. These data may be important for the management of these conditions and for counselling the patients toward further pregnancy.