Pregnancy and the Quad Marker Screen
What Substances Are Measured During a Quad Marker Screen? continued...
The expected amount of these substances normally found in the mother's bloodstream changes weekly during pregnancy, so it is important to tell your health care providers how far along you are in your pregnancy. High AFP levels may indicate that the baby has an open neural tube defect. High AFP levels may also indicate that the fetus is older than was thought or that the woman is expecting twins. Lower than normal AFP levels could indicate that a woman is at higher risk for having a baby with Down syndrome.
Levels of hCG and Inhibin-A are higher than normal when a woman has an increased risk of having a baby with Down syndrome. Lower than normal levels of estriol (a hormone) may also indicate that a woman is at high risk for having a baby with Down syndrome.
Is the Quad Marker Screen Safe?
Yes. The quad marker screen is a safe and useful screening test for families concerned about birth defects or genetic diseases. It is a test that carries no risk to the baby, since a blood sample is taken only from the mother.
What Does It Mean if the Quad Marker Screen Results Are Normal?
Normal levels of AFP, estriol, hCG, and Inhibin-A strongly indicate that you have a healthy pregnancy and a healthy baby. In over 98% of pregnancies, normal quad marker screen results predict healthy babies and births without major complications. However, there are no prenatal tests that can guarantee your baby and pregnancy will be completely healthy or without complications.
What Does It Mean if the Quad Marker Screen Results Are Abnormal?
Quad marker screen results that are not in the normal range do not necessarily mean there is a problem in your pregnancy.
The quad marker screen is used as a screening tool only, which means it can only assess your risk of having a baby with a certain birth defects (it is not used to diagnose the particular problem that may be present). If the quad marker screen results are not in the normal range, further tests such as an ultrasound or amniocentesis may be necessary.
Out of 1,000 pregnant women, approximately 50 will have quad marker screen results that indicate an increased risk for having a baby with a birth defect. Of those 50 women, only one or two will actually have a baby with an open neural tube defect. About 40 women will have quad marker screen results that show an increased risk for having a baby with Down syndrome and one or two will actually have a baby with Down syndrome.