Triple Screening In Pregnancy – What It Is and What To Expect?
There are several screening tests performed throughout pregnancy. Some of these screening tests are a part of the regular prenatal check-up while there are some screening tests performed to determine the chances of congenital disabilities in an unborn baby. One such screening test is the triple screen test. This test gives the clue of possible abnormality in the fetus and whether to proceed with further tests to confirm if the pregnancy is risky. Continue reading to know all about the triple screen test.
What is the triple screen test?
A triple screen test is a non-invasive procedure. It is a simple blood test that checks the following
Human chorionic gonadotropin (hCG)
Unconjugated estriol (uE3)
It helps the doctor to ascertain the possibility of the developing baby to be born with certain birth defects. Let us see what these substances are and how their levels help in finding the birth defects in the fetus.
Alpha-fetoprotein (AFP): It is a protein produced by the unborn baby’s liver. AFP enters the amniotic fluid and the pregnant woman’s bloodstream. It is normal to find some traces of this protein in a pregnant woman’s blood. High amounts of this protein can indicate certain possible birth defects like the neural tube defects or congenital problems like the baby’s intestine sticking out through the belly wall. Likewise, the lower levels of AFP indicates the possibilities of Down syndrome
Human chorionic gonadotropin (hCG): It is a hormone that is produced in the placenta of a woman when she becomes pregnant. Low levels of hCG can be a sign of significant issues with the pregnancy, like a miscarriage or ectopic pregnancy. High levels of hCG can sometimes indicate molar pregnancy or could be due to multiple pregnancies
Estriol (uE3): Estrogen called estriol increases throughout pregnancy. The placenta and the fetus produce it. Low estriol levels can be a sign of a baby having Down syndrome, particularly when the pregnant woman also has low levels of AFP and high levels of hCG
The AFP, estriol, and hCG values alone are not conclusive in finding out the possibility of birth defects. These levels, along with maternal age and factors like gestational age, mother’s weight, if she is diabetic, etc. are also taken into consideration to determine the chances of the fetus having a birth defect.
Who Is Recommended The Triple Screen Test?
All pregnant women are offered the triple screen test. However, the test is recommended, if the pregnant women:
is affected by any viral infection during pregnancy
When And How Is Triple Screen Test Performed?
The triple screen test normally performed between the 15th to 20th weeks of pregnancy. The test is considered most accurate if performed between the 16th to 18th weeks. The results of the test are usually obtained within 48 to 96 hours. The simple test involves drawing blood samples from the pregnant woman’s bloodstream and testing them in a laboratory. This screening test is noninvasive, and hence, it is perfectly safe.
How Accurate Is the Triple Test In Pregnancy?
The triple screen test accurately finds out 80% of spina bifida
This test correctly finds out 90% of anencephaly
Though it misses 31 fetuses out of 100 who have Down syndrome, on the brighter side, it detects 69% of the fetus who has it
The negative screening result, even though, indicates that no further tests are needed because the baby has no risk of any birth defects, it does not assure 100% guarantee and can sometimes be a false-negative test result also
What Do Results Of Triple Screen Test Indicate?
The positive results mean an increased risk of chromosomal and neural birth defects and would require further diagnostic tests like amniocentesis to confirm the same. But these further tests are optional.
Should You Have The Triple Screening Done During Pregnancy?
Whether to take the triple screen test or not is totally your own decision and indeed a tough choice to make. You should consider whether the positive results of this test would hold any meaning to and your spouse and in what ways will it affect your pregnancy.
If you decide to go ahead with the test, you can consult a genetic counselor. He can have a detailed discussion with you and your spouse and reason out with you both whether to go ahead with the test or not, thus helping you in decision making.
Some couples opt out of this test or additional testing for various reasons:
They are ok with the results whatever the outcome is
Due to personal, moral, or religious reasons, they will carry the baby to term, and thus the results don’t matter
With the risk of these tests harming the developing baby, some parents choose not to allow any testing
It is important to thoroughly discuss the risks and benefits of testing with your doctor and evaluate if the benefits from the results outweigh any risks from the procedure before taking this test.