Advances in genetic prenatal diagnosis and screening.

Abstract

Prenatal diagnostic and screening tests are routinely offered to all women in pregnancy. Advances in technology have led to an expansion in available testing. As technology improves, women are facing increasingly complex decisions regarding the quantity and quality of information they wish to have regarding their fetus. Professional guidelines support the use of chromosomal microarray analysis as a first-tier test in place of standard karyotype for the evaluation of fetal chromosomes when one or more anomaly is detected by ultrasound. These same guidelines indicate that either chromosomal microarray analysis or standard karyotype can be offered for prenatal diagnosis with a phenotypically normal fetus. Additionally, recent work continues to validate the use of noninvasive prenatal testing for the detection of aneuploidy in the high-risk population. This testing utilizes cell-free DNA in the maternal circulation to predict fetal karyotype with greater sensitivity and specificity than maternal serum screening or first trimester screening. Data continue to accumulate supporting noninvasive prenatal testing use in an all-risk or low-risk population. Additionally, noninvasive prenatal testing is clinically available to screen for a select number of microdeletion syndromes, broadening the scope of population-based screening to include conditions not previously evaluated, although there are limited data available regarding this application. As prenatal diagnosis becomes increasingly complex, there is a need for the education of both patients and providers regarding the benefits and limitations of the testing strategies available to them.