Prenatal diagnosis of chromosomal abnormalities: analysis of 1000 consecutive amniotic fluids.

Cytogenetic studies have been performed on 1,000 amniotic fluid specimens referred for prenatal diagnosis. Two-thirds of the patients had strong clinical indications for prenatal chromosome studies and the remaining one-third were referred because of maternal anxiety or a family history of neural tube defect. A total of 18 affected fetuses were detected in this series (1.8%) and these included 3 male fetuses in patients with a history of sex-linked disorder and 15 fetuses with chromosome abnormalities. The overall culture success rate was 97.4% and the average time taken to obtain sufficient material for initial chromosome analysis was 13 days. Fetal loss within 4 weeks of the amniocentesis was 1.2%.