Rapid cytogenetic assessment of fetal blood samples.

OBJECTIVE

To obtain a timely fetal karyotype in selected circumstances by investigating the usefulness of fetal blood samples.

METHODS

Forty-five patients had fetal blood sampling for a variety of abnormalities including hydrocephalus, oligohydramnios, fetal growth retardation, nonimmune hydrops, duodenal atresia, polyhydramnios, and multiple anomalies. Four cytogenetic techniques were attempted in determining fetal karyotype: a direct harvest of lymphocytes in the fetal blood sample, a 24-hour incubation of fetal lymphocytes without mitogen, and a 48- and 72-hour mitogen-stimulated incubation followed by harvest and analysis.

RESULTS

Ten of these 45 cases showed diagnostic cytogenetic abnormalities. Twenty-nine cases had results reported within 30 hours of obtaining the specimen following analysis of unstimulated cultures. One-half of the abnormal results were reported within 30 hours of receiving the specimen.

CONCLUSION

Unstimulated lymphocyte cultures from fetal blood samples may provide rapid cytogenetic diagnosis and alter obstetric management in selected circumstances.