This is a blood test that measures the amount of three substances in a pregnant woman's blood. These substances are produced by the baby or the placenta and enter the mother's bloodstream through the placenta. The test determines if the baby is at risk for having an open neural tube defect such as spina bifida, or down syndrome, a hormonal abnormality. If the test indicates that a risk does exist, it does not mean that the baby has either of these conditions. In most situations this will not be the case.
Further testing is needed to determine if, indeed, the baby is affected.
Women with a family history of Down Syndrome, or who are 35 or older are at greater risk of having an affected baby. Babies born with Down Syndrome have a distinct appearance, some degree of mental retardation and other birth defects that may include heart and digestive tract abnormalities. The risk of Down Syndrome is determined by measuring the amounts of AFP, HCG and UE3 present in the blood sample in relation to the mother's age. If the mother is 35 or older, or she has a family history of Down Syndrome, she may be offered amniocentesis instead of the triple screen test. Neural tube defects are birth defects that involve the brain or the spinal cord.