ACOG Practice Bulletin No. 162: Prenatal diagnostic testing for genetic disorders. Obstet Gynecol. 2016;127(5):e108-e122. PMID: 26938573pubmed.ncbi.nlm.nih.gov/26938573/. Show
Driscoll DA, Simpson JL. Genetic screening and prenatal genetic diagnosis. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 10. Wapner RJ, Dugoff L. Prenatal diagnosis of congenital disorders. In: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 32. Williams DE, Pridjian G. Obstetrics. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier; 2016:chap 20. Last reviewed on: 1/10/2022 Reviewed by: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The multiple marker test is a blood test offered to all pregnant women. Doctors use it to screen for chromosomal disorders and neural tube defects. Test results can be combined with first trimester screening tests to give more accurate results (this is called an integrated screening test). It is important to remember that this is a screening test, not a diagnostic test. If the test shows there might be a problem, another test must be done to confirm or rule out a diagnosis. Why Is the Multiple Marker Test Done?The multiple marker test is done between weeks 15 and 20 of a woman's pregnancy to screen for neural tube defects (such as spina bifida) and chromosomal disorders (such as Down syndrome and trisomy 18). Depending on the number of things measured, the test also is called:
This screening calculates a woman's individual risk based on the levels of the three (or more) substances, as well as:
The greater number of markers increases the accuracy of the multiple marker test and better identifies the possibility of a problem. In some cases, doctors will combine the results of this test with results from the first trimester screen to get an even better idea of a baby's risk for Down syndrome and neural tube defects. Should I Have the Multiple Marker Test?All pregnant women are offered some form of this test. Some health care providers include more parts of it than others. Remember that this is a screening test, not a diagnostic test. It's also not foolproof — a problem might not be detected, and some women with abnormal levels are found to be carrying a healthy baby. Further testing is recommended to confirm a positive result. The triple marker screen test is also known as the triple test, multiple marker test, multiple marker screening, and AFP Plus. It analyzes how likely an unborn baby is to have certain genetic disorders. The exam measures the levels of three important substances in the placenta:
Triple marker screening is administered as a blood test. It’s used for women who are between 15 and 20 weeks pregnant. An alternative to this test is the quadruple marker screen test, which also looks at a substance called inhibin A. What does a triple marker screen test do?A triple marker screen test takes a sample of blood and detects the levels of AFP, HCG, and estriol in it. AFP: A protein produced by the fetus. High levels of this protein can indicate certain potential defects, such as neural tube defects or failure of the fetus’s abdomen to close. HGC: A hormone produced by the placenta. Low levels may indicate potential problems with the pregnancy, including possible miscarriage or ectopic pregnancy. High levels of HGC can indicate a molar pregnancy, or a multiple pregnancy with two or more children. Estriol: An estrogen that comes from both the fetus and the placenta. Low estriol levels may indicate risk of having a baby with Down syndrome, especially when paired with low AFP levels and high HGC levels. Abnormal levelsAbnormal levels of these substances may indicate the presence of:
Abnormal levels can also indicate Down syndrome or Edwards syndrome. Down syndrome occurs when the fetus develops an extra copy of chromosome 21. It can cause medical problems and, in some cases, learning disabilities. Edwards syndrome can result in extensive medical complications. These are sometimes life-threatening in the first months and years after birth. Only 50 percent of fetuses with this condition survive to birth, according to the Trisomy 18 Foundation. Who benefits from the triple marker screen test?Triple marker screen tests help prospective parents prepare and assess options. They also alert doctors to watch a fetus more closely for other signs of complications. The test is often most recommended for women who:
What preparation is involved for a triple marker screen test?Women do not need to prepare for a triple marker screen test. There are no eating or drinking requirements beforehand. Moreover, there are no risks associated with taking the triple marker screen test. How is a triple marker screen test administered?The triple marker screen test is administrated in a hospital, clinic, doctor’s office, or lab. The process is similar to any other blood test. A doctor, nurse, or lab technician cleans the patch of skin where they will insert the needle. They will likely place a rubber band or other tightening device on your arm to make a vein more accessible. The health professional then inserts the needle to draw blood, and they remove it when the vial is full. They clean the site of injection with a cotton swab or other absorbent material and put a bandage on the wound. The blood is then sent to a lab for assessment. There are no side effects for triple marker screen tests. You may experience slight discomfort due to the needle used to take blood, but that fades quickly. What are the benefits of a triple marker screen test?A triple marker screen test can indicate potential complications with a pregnancy, as well as the presence of multiple fetuses. This helps parents prepare for birth. If all the test results are normal, parents know that they are less likely to have a child with a genetic disorder. What are the results of a triple marker screen test?The results of the triple marker screen test show the likelihood of an infant having a genetic disorder such as Down syndrome or spina bifida. Test results aren’t infallible. They merely show a probability, and may be an indication for additional testing. Doctors often consider several other factors that can affect the test results. These include:
Next steps Parents who receive negative indicators on their triple marker screen test must then decide what actions to take. While abnormal results can be concerning, they don’t necessarily mean that there’s anything to worry about yet. Instead, they’re a good indication to explore further testing or monitoring. In the case of abnormal results, an amniocentesis test may be ordered. In this test, a sample of amniotic fluid is taken from the uterus via a thin, hollow needle. This test can help detect genetic conditions and fetal infections. If your results show high levels of AFP, your doctor will likely order a detailed ultrasound to examine the fetal skull and spine for neural tube defects. Which of the following tests can be used to indicate whether a fetus is developing normally?Your health care provider can use ultrasound to determine whether your baby is growing at a normal rate. Ultrasound can be used to monitor your baby's movement, breathing and heart rate. Study the placenta and amniotic fluid levels.
Which psychological approach emphasizes the importance of adaptation reproduction and survival?Evolutionary approach uses evolutionary ideas such as adaptation, reproduction, and natural selection as the basis for explaining specific human behaviors.
Which of the following is the main risk factor that a couple must be aware of when undergoing fertility treatments quizlet?Which of the following is the main risk factor that a couple must be aware of when undergoing fertility treatments? An increase in the possibility of multiple births when such treatments are used.
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The current maternal blood screening test is called the triple screen because
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