Chromosomal microarray analysis and prenatal diagnosis.

Chromosomal microarray analysis (CMA) assesses chromosomal copy number alterations and affords higher resolution when compared with standard karyotype. This review provides the obstetric provider with an update on the technology, use, and controversies concerning CMA utilization in prenatal diagnosis. Chromosomal microarray analysis offers increased resolution for copy number abnormalities compared with traditional karyotype. There is high-quality evidence for the added detection of clinically significant copy number alterations with CMA in prenatal diagnosis when the traditional karyotype is normal. Other potential advantages of CMA include a quicker turnaround time and utilization in clinical situations with a high probability of nondividing cells (ie, intrauterine fetal demise, spontaneous miscarriage, and third-trimester amniocentesis). Chromosomal microarray analysis may be beneficial when prenatally detected structural anomalies are associated with specific microdeletions and microduplications or to assess for copy number variants when a de novo balanced rearrangement or marker chromosome is diagnosed. Use of CMA includes the detection of copy number variants of uncertain significance. In light of these issues, large prospective cohort studies are needed to illustrate the diagnostic utility of CMA for detection of prenatal chromosomal abnormalities in low-risk populations before routine clinical use of CMA is recommended in all circumstances of prenatal diagnosis.