Definition:This is a blood test that measures the levels of alpha-fetoprotein (AFP), a protein released by the fetal liver and found in the mother’s blood. AFP is sometimes called MSAFP (maternal serum AFP ) This blood test for pregnant women, also called a “triple screen,” checks the levels of protein and hormones being produced by the fetus. The levels of three different substances together can enable doctors to identify pregnancies that are at a higher risk for birth defects such as Down syndrome or neural tube defects (brain and spinal cord problems). If the blood test suggests problems, your doctor might recommend additional tests, such as amniocentesis or fetal ultrasound, to confirm the findings.
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The alpha-fetoprotein (AFP) test is available to women between their 15th and 20th week of pregnancy to screen for fetal abnormalities. This simple blood test measures the level of a protein called alpha-fetoprotein which is secreted by the liver of the fetus and enters the mother’s blood stream. Elevated levels of AFP may indicate an increased risk of neural tube defects such as spina bifida or anencephaly, while low levels suggest Down Syndrome or other chromosomal defects.
The AFP test does not determine the existence of these genetic disorders; it only predicts their likelihood. And while the AFP test is most often used to screen for these defects, it can also be used to identify abdominal wall defects, some renal and urinary tract abnormalities, Turner syndrome, low birth weight, and placental complications. An incorrectly-calculated gestational age and multiple fetuses can also cause abnormal AFP levels.
How do you prepare for the test?
* Before having this test done, you need to think carefully about what you would do with the results once you have them. The results of this blood test cannot show for sure whether you have either a healthy fetus or one with a problem; it can only suggest which patients might want to go ahead with further testing. Because amniocentesis (the test that is usually recommended after an abnormal triple screen) has a small risk of miscarriage, and because most people with an abnormal triple screen decide to go ahead with amniocentesis, this is an important decision. You should have this test done only if you think the information it offers would help you to make decisions about your pregnancy.
What happens when the test is performed?
* Your blood is drawn for this test sometime between your 15th and 20th weeks of pregnancy. The blood is tested for three protein and hormone levels: maternal serum alpha fetoprotein (MSAFP), unconjugated estriol (uE3), and human chorionic gonadotropin (hCG). Your doctor needs to weigh you on the day you have your blood drawn and ask when your last period began or what your expected due date is. The analysis of the results will take into account your weight and stage of pregnancy to determine whether the levels are normal.
What risks are there from the test?
* There are no risks from this test itself, but there are some risks from tests that might be recommended if the test result comes back abnormal (see-> “Amniocentesis,” ). This test can be stressful for expectant parents. Several things can cause the test to come back as abnormal even when there are no real health problems. Confusing results can happen, for example, in twin pregnancies and when mistakes have been made in estimating the age of the pregnancy.
How long is it before the result of the test is known?
The test results are available to your doctor within two or three days.
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Health informations for pregnant women:
Pregnancy & Childbirth :
Integrated test during pregnancy:
Common Tests During Pregnancy:
Glossary: From “abdomen” to “zygote,” here’s your guide to pregnancy terminology. :
High-Risk Pregnancy :
Healthy & Safe Pregnancy :
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