Prenatal diagnosis or prenatal screening (note that prenatal diagnosis and prenatal screening refer to two different types of tests) is testing for diseases or conditions in a fetus or embryo before it is born. The aim is to detect birth defects such as neural tube defects, Down syndrome, chromosome abnormalities, genetic disorders and other conditions, such as spina bifida, cleft palate, Tay–Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, Muscular dystrophy, and fragile X syndrome. Screening can also be used for prenatal sex discernment. Common testing procedures include amniocentesis, ultrasonography including nuchal translucency ultrasound, serum marker testing, 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 tertiary care hospital where the baby can receive appropriate care.