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amniocentesisAmniocentesis is generally recommended when there is a family history of genetic disorders or when the woman is over age 35 and therefore at a higher risk of having a baby with a chromosomal abnormality. The procedure is usually carried out around the 14th or 15th week of pregnancy, when there is sufficient amniotic fluid and abortion is still an option. It can also be used in the third trimester (after 30 weeks) when Rh incompatibility (see erythroblastosis fetalis) is suspected, or to determine the status of the fetus in early or late delivery or when there are signs of fetal distress.
See also birth defects; chorionic villus sampling; embryo biopsy.
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- birth defects
Birth defects, abnormalities in physical or mental structure or function that are present at birth. They range from minor to seriously deforming or life-threatening. A major defect of some typ...
- chorionic villus sampling
Chorionic villus sampling (CVS) or chorionic villus biopsy (CVB), diagnostic procedure in which a sample of chorionic villi from the developing placenta is removed from the uterus of a pregnan...
- Down syndrome
Down syndrome, congenital disorder characterized by mild to severe mental retardation, slow physical development, and characteristic physical features. Down syndrome affects about 1 in every 7...
- embryo biopsy
Embryo biopsy or preimplantation genetic diagnosis (PGD), diagnostic procedure, used in genetic screening, in which a single cell is removed from an embryo two or three days after it has been ...
- eugenics
Eugenics, study of human genetics and of methods to improve the inherited characteristics, physical and mental, of the human race. Efforts to improve the human race through bettering housing f...
- genetic screening
Genetic screening, testing for genetic disorders. Most commonly, prospective parents or an embryo or fetus is tested when a specific genetic disorder is suspected (e.g., Tay-Sachs or sickle ce...
- pregnancy
Pregnancy, period of time between fertilization of the ovum (conception) and birth, during which mammals carry their developing young in the uterus (see embryo). The duration of pregnancy in h...
- Tay-Sachs disease
Tay-Sachs disease, rare hereditary disease caused by a genetic mutation that leaves the body unable to produce an enzyme necessary for fat metabolism in nerve cells, producing central nervous ...
- muscular dystrophy
Muscular dystrophy, any of several inherited diseases characterized by progressive wasting of the skeletal muscles. There are five main forms of the disease. They are classified according to t...
