Fetal chromosome analysis in Virginia: results and complications of 2,288 cases.

In reviewing the results and complications of 2,288 consecutive fetal chromosome analyses at the Medical College of Virginia, we found that 48 abnormal fetuses (2.1%) were detected, with age-specific and indication-specific incidences of particular abnormalities (such as Down's syndrome and structural rearrangement) similar to those found in other large series. An unusual finding was a 5.5% incidence of aneuploidy among 55 patients who had antenatal testing because of a history of neural tube defects. The spontaneous abortion rate after amniocentesis was 2.5% from 1976 to 1981, but only 0.9% in 1982 to 1983. Adequate karyotypes were obtained in 99.6% of patients; there were no laboratory misdiagnoses. We discuss the present impact of fetal karyotyping in Virginia, as well as the implications for pregnancy surveillance in the future of the decreasing morbidity of midtrimester amniocentesis and technologic improvements in obstetrics, such as ultrasonography and chorionic villus biopsy.