Prenatal cytogenetic diagnosis of 1,400 consecutive amniocenteses.

We report on the incidence of chromosomal abnormalities in 1,400 amniocenteses. Thirty-one cases (2.21%) were found to have various types of chromosomal abnormality. The majority of abnormal cases (54.84%) were trisomies. All individuals with trisomic fetuses chose to terminate the pregnancy with the exception of one who gave birth to a Down's syndrome child. However, fetuses with apparently balanced translocations were phenotypically normal at birth.