amniocentesis<\/a>. Invasive tests increase the risk of miscarriage in the second trimester. Quad screen test gives a fair hint of the risk without the danger of inducing a miscarriage.<\/p>Some women wait for their first prenatal checkup until the time they’re ready for Quad Screen. When both the tests are together, the results are more conclusive. Combined test is integrated or sequential screening.<\/p>
What does a Quad screen look for?<\/h2>
The Quad Screen looks for:<\/p>
- AFP:<\/strong> Alpha-Fetoprotein which is a protein that is produced by the baby’s liver and other organs. The higher levels of AFP show a risk of neural tube defect. By the 15th week, AFP starts appearing in the blood of the mother. You can get your Quad Screen until the 20-21 week of the second trimester. With AFP you may come to know if you’re carrying twins. At times the age of baby continues to be miscalculated until the second trimester. For those who get a sequential screening, it’s the first time they know how old is the baby. High AFP values also mean that the baby is older than what you came thinking. Problems in the excretory system such as kidney also lead to elevated AFP values. When a part of the brain or spine doesn’t form, anencephaly, AFP production increases.<\/li>
- hCG:<\/strong> the placenta produces human Chorionic Gonadotropin after the implantation<\/a> of the egg. You test it when you use the pregnancy kit. By the second trimester, the hormone reaches its peak with a gradual increase in doubling time. After attaining the peak value, hCG begins to decline. When the levels of hCG continue to be high in the stage, there is a risk of Downs Syndrome. The disorder leads to severe abnormalities and development lapses in the baby. Downs Syndrome occurs because of trisomy of chromosome 21. All genetic material is in the form of pairs of chromosomes. Trisomy means three chromosomes instead of two. Reduced hCG indicates that there is a risk of Edwards Syndrome. There is a wide normal range no pinpoint value, so you don’t have to worry about it.<\/li>
- Unconjugated Estriol:<\/strong> There are three types of estrogen E1, E2, and E3. Both men and women have estriol. During pregnancy E 3 dominates the other two types. Low levels of E3 in the second trimester indicate the chances of having fetal adrenal defects, neural tube defects, ichthyosis, cholesterol synthesis abnormalities, and miscarriage. High levels of estriol in Quad Screen mean the risk of preterm labor. It also shows the possibility of congenital adrenal hyperplasia. In the condition, additional tissues reduce the number of hormones produced by the adrenal gland.<\/li>
- Inhibin A:<\/strong> Earlier the Quad Screen was a triple screen. With the addition of inhibin A to the multiple marker screening, it’s now a quad. Inhibin has two types A and B. The levels of Inhibin A along with the other parameters of Quad screen are the marker for Down\u2019s Syndrome in early pregnancy. The New England Journal of Medicine has published Dimeric Inhibin A as a Marker for Down’s Syndrome in Early Pregnancy.<\/em>