The Use of Chromosomal Microarray Analysis in Prenatal Diagnosis.

Chromosomal microarray analysis (CMA) identifies microdeletions and duplications undetected on karyotype analysis. Copy number variants (CNVs) occur in 1% to 1.7% of all pregnancies, with clinical implications. All women undergoing invasive testing for routine indications should be offered microarray. Clinically significant CNVs are seen in approximately 6% of pregnancies with ultrasound anomalies, making CMAs the current standard of cytogenomic analysis. Clinicians should be familiar with different technologies and laboratory reporting practices. Pretest counseling is imperative and, when CMA results are abnormal, posttest counseling should be in-depth and conducted by a genetic counselor or clinical geneticist.