Prenatal diagnosis of nuchal cystic hygroma.

Twenty-seven cases of nuchal cystic hygroma were diagnosed prenatally over a 5-year period at the Birmingham Maternity Hospital. Karyotypes were obtained in 20 cases, of which 14 (70%) were abnormal. Two-thirds of these represented various trisomy syndromes in contrast to other series where cases of Turner's syndrome have predominated. Twenty pregnancies were terminated. There was one intra-uterine death and two neonatal deaths. Hydrops was present in 15 cases, none of which survived to term. Associated structural abnormalities, mainly skeletal, renal and cardiac, were present in 18 cases. There were four long-term survivors with good quality of life, including both normal and abnormal karyotypes. In utero regression of the hygroma was documented in five cases, total in three and subtotal in two cases born with residual neck webbing.