Recent Trends in Prenatal Diagnosis of Fetal Malformations

ABSTRACT

The frequency of fetal malformations accounts for around 3~5% and evaluation of the health of the fetus and screening for fetal malformations has become an important part of prenatal care. Fetal malformations can be classified into structural and chromosomal abnormalities. Improvements in prenatal diagnosis have allowed identification of malformations in fetuses during the first and second trimesters of pregnancy. In prenatal diagnosis, both screening and diagnostic procedures are included. Screening tests include maternal serum aneuploidy screening tests, which are double marker test, triple test, and quadruple test. Recently, first trimester combined ultrasound-biochemical screening and integrated screening were introduced and provided higher detection rates of chromosomal anomalies (ex. Down syndrome). Diagnostic tests are usually performed when screening results are positive and they include chorionic villus sampling, amniocentesis, and percutaneous fetal blood sampling. With highresolution ultrasound equipment, it is now possible to diagnose most structural abnormalities prenatally. On top of that, recent advances in 3D/4D ultrasound have allowed better understanding of fetal anatomy. However, when ultrasound is equivocal, fetal MRI also can be a useful adjuvant in evaluating fetal structural anomalies. Advances in prenatal diagnostic testing have resulted in tremendous benefits to patients and challenges to healthcare providers and new approaches to education and counseling are needed to assure that all patients receive a complete and balanced review of their prenatal diagnostic testing options. This article provides an overview of various screening and diagnostic methods for prenatal diagnosis of fetal malformations.