Genetic diagnosis Early in pregnancy,<unk>  is used for diagnosis of chromosomal, genetic, and other fetal problems such as: * Down syndrome, also known as Trisomy 21 * Trisomy 13 * Trisomy 18 * Sex chromosome aneuploidies, also known as sex chromosome anomalies * Fragile X * Neural tube defects (anencephaly and spina bifida) by alpha-fetoprotein levels. * Rare, inherited metabolic disorders Lung development<unk>  can be used to test fetal lung development. Problems with lung development can increase the risk of infant respiratory distress syndrome. Fetal lung development can be tested by sampling the amount of surfactant in the<unk> iotic fluid in pregnancies greater than 30 weeks. Several tests are available, including the lecithin-sphingomyelin ratio ("L/S ratio"), the presence of phosphatidylglycerol (PG), or the surfactant/albumin (S/A) ratio. * For the L/S ratio, if the result is less than 2:1, the fetal lungs may be surfactant deficient. * The presence of PG usually indicates fetal lung maturity. * For the S/A ratio, the result is given as mg of surfactant per gm of protein. An S/A ratio 55 indicates mature surfactant production. Infection<unk>  can detect infections via decreased glucose level, a Gram stain showing bacteria, or abnormal differential count of white blood cells. Rh Incompatibility<unk>  can be used to diagnose Rh incompatibility, a condition when the mother has Rh-negative blood and the fetus has Rh-positive blood. Early detection is important to treat the mother with Rh immune globulin and to treat her baby for hemolytic anemia. Decompression of polyhydramnios Polyhydramnios, or the<unk> cumulation of<unk> iotic fluids which leads to increase risk of cesarean section, can be relieved via decompression<unk> .<unk>  can also be used to diagnose potential causes of polyhydramnios. Preterm rupture of membranes An emerging indication for<unk>  is in the management of preterm rupture of membranes where measurement of certain<unk> iotic fluid inflammatory markers may be helpful. If<unk> iotic fluid IL-6, a marker of inflammation, is elevated, the fetus is at high risk and delivery should be considered.
Amniocentesis
Magnetogenetics
Fetal echocardiography
Fetal scalp blood testing
Chorionic villus sampling
Prenatal testing
Preimplantation genetic diagnosis
Obstetric ultrasonography