Fetal Origin Circulating Cell-Free Nucleic Acids in Maternal Circulation and Their Clinical Importance

Noninvasive prenatal screening (NIPS), an evolving method in prenatal testing, relies on fetal-origin circulating cell-free nucleic acids (cfNAs), including DNA and RNA. The primary molecule in NIPS is cell-free fetal DNA (cffDNA), while cell-free fetal RNA (cffRNA) has also gained significance. cffDNA persists in maternal plasma, exhibiting variations in quantity during pregnancy and alterations in specific conditions. cffRNA, a rich source of genetic information, finds applications in assessing gene expression patterns and detecting disorders. Originally, limited to chromosomal aneuploidies, NIPS now extends to disorders such as preeclampsia and gestational diabetes. Technological advancements, including polymerase chain reaction, sequencing, and microfluidics, enhance cfNAs’ use in NIPS. This chapter delves into cffNAs and their clinical applications in prenatal screening.