PMID: pubmed. Genetic screening and prenatal genetic diagnosis. Gabbe's Obstetrics: Normal and Problem Pregnancies. Philadelphia, PA: Elsevier; chap Wapner RJ, Dugoff L.
Prenatal diagnosis of congenital disorders. Williams DE, Pridjian G. Textbook of Family Medicine. Reviewed by: John D. Editorial team. Quadruple screen test Quad screen; Multiple marker screening; AFP plus; Triple screen test; AFP maternal; MSAFP; 4-marker screen; Down syndrome - quadruple; Trisomy 21 - quadruple; Turner syndrome - quadruple; Spina bifida - quadruple; Tetralogy - quadruple; Duodenal atresia - quadruple; Genetic counseling - quadruple; Alpha-fetoprotein quadruple; Human chorionic gonadotropin - quadruple; hCG - quadruple; Unconjugated estriol - quadruple; uE3 - quadruple; Pregnancy - quadruple; Birth defect - quadruple; Quadruple marker test; Quad test; Quadruple marker screen.
How the Test is Performed This test is most often done between the 15th and 22nd weeks of the pregnancy. The test measures levels of 4 pregnancy hormones: Alpha-fetoprotein AFP , a protein produced by the baby Human chorionic gonadotropin hCG , a hormone produced in the placenta Unconjugated estriol uE3 , a form of the hormone estrogen produced in the fetus and the placenta Inhibin A, a hormone released by the placenta If the test does not measure levels of inhibin A, it is called the triple screen test.
To determine the chance of your baby having a birth defect, the test also factors in: Your age Your ethnic background Your weight Your baby's gestational age measured in weeks from the day of your last period to the current date.
How to Prepare for the Test No special steps are needed to prepare for the test. How the Test will Feel You may feel slight pain or a sting when the needle is inserted. Why the Test is Performed The test is done to find out if your baby might be at risk for certain birth defects, such as Down syndrome and birth defects of the spinal column and brain called neural tube defects. Certain women are at greater risk of having a baby with these defects, including: Women who are over 35 years old during pregnancy Women taking insulin to treat diabetes Women with a family history of birth defects.
Registry Builder New. The Quad Screen. Medically Reviewed by Jennifer Wu, M. Medical Review Policy All What to Expect content that addresses health or safety is medically reviewed by a team of vetted health professionals. The quad screen tests four factors in your blood to help you make a decision about further genetic testing.
Back to Top. In The Article. The quad screen is a blood test that measures the levels of four substances produced by the fetus and the placenta and passed into the mother's bloodstream: Alpha-fetoprotein AFP , a protein made by the baby Human chorionic gonadotropin hCG , a hormone created by the placenta Estriol, a form of estrogen produced by the placenta and baby Inhibin A, a hormone made by the placenta Together they are entered into a formula that tells you what the probability is that you are carrying a child with a chromosomal abnormality — specifically:.
Continue Reading Below. More About Prenatal Testing. Nuchal Translucency Screening. Prenatal Testing During Pregnancy. View Sources. Mayo Clinic, Quad Screen , November Pregnancy Groups. That is, it may identify your baby as being at high risk for one of these three problems when she is fine. This may cause you to undergo further testing and to worry about your baby's well-being unnecessarily.
A genetic counselor or maternal-fetal medicine specialist can help you understand your results and your options. You may want to discuss the pros and cons of undergoing amniocentesis to find out whether your baby does have a problem.
But you'll most likely be offered a detailed sometimes called level II or targeted ultrasound first. This test can give you some more immediate information.
If you have high AFP , a level II ultrasound will enable the doctor to check your baby's spine and other parts for defects. It will also confirm your baby's age and whether you're carrying twins. If the ultrasound shows that your baby is younger or older than your practitioner thought or that you're carrying more than one baby, your results will be recalculated.
If your baby is found to have spina bifida or another birth defect and you decide to continue the pregnancy, your medical team will be able to monitor your baby's condition during your pregnancy and prepare to do surgery once he's born.
If your baby is screen-positive for Down syndrome or trisomy 18 , the ultrasound can enable your doctor to check for several "markers" that may suggest Down syndrome and other chromosomal disorders. If one or more of these markers are found, the likelihood of your baby having a genetic abnormality is increased. A baby with a major structural abnormality, such as a defect in the heart or abdominal wall, is also more likely to have a chromosomal defect.
If everything looks normal on the detailed ultrasound, it's still not a guarantee that everything is okay, but it does mean that your baby has a lower risk of chromosomal defects than your screening results indicate.
This information may help you decide whether to go ahead with amniocentesis. BabyCenter's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organizations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing.
Learn more about our editorial and medical review policies. Genetic disorders. American College of Obstetricians and Gynecologists. Prenatal genetic diagnostic tests. Prenatal genetic screening tests. Quad screen. Johns Hopkins Medicine. Common tests during pregnancy. Mayo Clinic. Medline Plus. Quadruple screen test. Merck Manual Overview of genetic disorders.
Join now to personalize. The quad screen is a second trimester blood test that measures the levels of four substances in your blood to tell you if your baby is at increased risk for Down syndrome and a few other conditions. If the results are "positive" you can have an amnio to tell you for sure about your baby's condition. Photo credit: iStock. What is the quad screen?
0コメント