Diagnosing a genetic abnormality as the cause of miscarriage allows for recurrence risk counseling, reduces parental feelings of guilt, and eliminates the need for further workup. Unfortunately, maternal cell contamination and culture failure both complicate testing done by traditional chromosome analysis.
Based on a review of the medical literature, existing professional society practice guidelines, chromosome abnormality detection rates using different test methods, and the cost and insurance provider landscapes, the Clinical Cytogenomics Laboratory has developed new recommendations for genetic testing of fetal tissue and products of conception. This tiered testing approach takes advantage of cytogenomic microarray analysis (CMA) and interphase fluorescence in situ hybridization (IFISH), methods which have advantages over karyotyping. Neither requires living cells, producing a higher success rate of obtaining results. Neither requires culturing, allowing detection of monosomies and multiple aneuploidies that aren’t viable in culture. And results are thus less susceptible to maternal cell contamination and culturing artifacts. CMA has a further advantage in that it detects subchromosomal alterations not visible with karyotyping.