Prenatal diagnosis is testing for diseases or conditions in a fetus or embryo before it is born. The aim is to detect birth defects such as spinal tube defects, Down syndrome, chromosome abnormalities, genetic diseases and other conditions. Screening can also be used for prenatal sex discernment. Common testing procedures include amniocentesis, ultrasonography or genetic screening. In some cases, the tests are administered to determine if the fetus will be aborted, though physicians and patients also find it useful to diagnose high-risk pregnancies early so that delivery can be scheduled in a way where the baby can receive appropriate care.
Prenatal screening has also been done to determine characteristics generally not considered birth defects for e.g. sex selection. The rise of designer babies and parental selection for specific traits raises a host of bioethical and legal issues that are expected to dominate reproductive rights debates in the 21st century.
Prenatal testing includes both screening tests and diagnostic tests. Prenatal screening tests can identify whether your baby is more likely to have certain conditions — but they usually can’t make a definitive diagnosis. A diagnostic test is the only way to be sure of a diagnosis. Some diagnostic tests, such as chorionic villus sampling or amniocentesis, carry a slight risk of miscarriage.