Prenatal diagnosis is now an established part of modern obstetrical practice around the world. While the current definitive methods for prenatal diagnosis rely mainly on invasive procedures such as chorionic villus sampling and amniocentesis, such procedures carry a low but definite risk of fetal loss. As a consequence of the procedure-associated risk of miscarriage, prenatal diagnosis is currently limited to pregnant women with an increased likelihood of bearing an abnormal fetus. To extend the application of prenatal diagnosis to all pregnant women, it has been a long-sought goal of researchers worldwide to introduce safer methods for prenatal diagnosis, towards noninvasive prenatal diagnosis.