Prenatal Testing Procedures

Abstract This chapter is somewhat technical; it reviews the laboratory methodologies by which a prenatal diagnosis can be made and the clinical procedures whereby tissue is obtained. The main indications for prenatal cytogenetic diagnosis are the pregnant woman being of older childbearing age, parental heterozygosity for a chromosome rearrangement, the birth of a previous child with a chromosome defect, increased risk on maternal screening tests, and fetal anomaly detected on ultrasonography. The move to molecular methodology is noted. The remarkable advances in NIPT (noninvasive prenatal testing), such that this approach has now become routinely available, are canvassed. The chapter briefly discusses ethical questions in the delivery of prenatal diagnosis. It reviews the approaches in fetal chromosomal screening, by a combined ultrasound and blood biochemical analysis, and the secular changes associated with this.